[Carol]

Focusing on the breath moving past the lip or nostrils helps in the beginning perhaps, but the expansiveness of the four steps of Tetrad I altogether mean that nose-focus &tc. are a crutch, not a meditation object to become absorbed in.

again, Dave, i would suggest the very opposite

focusing on the breath moving past the lip or nostrils is not something experienced in the beginning

the reality of Anapanasati here has been mixed up with Goenka's methods of meditation

when the mind is established in the Noble Right Concentration, which makes letting go (vossaga) its object, the mind, by nature, converges with the breathing in & out because the breathing in & out becomes the mind's grossest sense object

as the breathing naturally calms, their comes a period of time, prior to entering the 2nd Tetrad, when the mind is only aware of the touch (sensation) of the breathing in & out at the nostril

this is the beginning of the genuine development of the (literal) one-pointedness that will become jhana and is the causal condition for the arising of rapture & happiness (steps 5 & 6)

therefore, focusing on the breath moving past the lip or nostrils is not something experienced in the beginning

instead, focusing on the breath moving past the lip or nostrils is something experienced at the end of the 1st Tetrad

I think the commentarial literature makes missteps here.

so you also disagree with the commentarial literature on the basis of believing feeling a sensory impact from your foot or knee is some kind of profound experience which forms an intrinsic part of the training in Step 3?

at least the commentarial literature in the form of the Vissuddhimagga correctly describes the tranquilising from the gross to the subtle

at least the Vissuddhimagga correctly keeps the breathing as the object in Step 3

correctly, the Vissuddhimagga describes matters such as sensory impacts arising from the feet, knees, etc, as not related to the practise

176. And here both the gross and subtle state and also [progressive]
tranquilizing should be understood. For previously, at the time when the bhikkhu
has still not discerned [the meditation subject], his body and his mind are
disturbed and so they are gross. And while the grossness of the body and the
mind has still not subsided the in-breaths and out-breaths are gross.

171. (iii) He trains thus: “I shall breathe in … I shall breathe out experiencing the
whole body”: he trains thus: “I shall breathe in making known, making plain,
the beginning, middle and end of the entire in-breath body. I shall breathe out
making known, making plain, the beginning, middle and end of the entire outbreath
body,” thus he trains. Making them known, making them plain, in this
way he both breathes in and breathes out with consciousness associated with
knowledge. That is why it is said, “He trains thus: ‘I shall breathe in … shall
breathe out …’”

the major shortcoming of the Vissuddhimagga is it does not instruct, as the Buddha did, the development of jhana by making vossaga (relinquishment; abandonment; letting go) the mind's object; that is, by making Right View the 'forerunner'

as a result, the Vissuddhimagga is instructing a form a "wrong concentration"

as a result, the Vissuddhimagga does not describe & understand the subtlety of step 3 as "all bodies" because wrong concentration, which uses the force of intent rather than the subtlety of letting go, cannot discern "all bodies"

but, apart from that, i cannot see how the description of the stages of progress in the Vissuddhimagga warrant your censure, as though sensory impacts from the feet or knees are somehow related to Step 3 and as though the mind "fixing" as the nostril is a beginner's practise

whilst the Anapanasati instruction in the Vissuddhimagga is quite immature and unsublime (being not based in vossaga), its description of the various stages of development do conform with the natural reality of breath tranquilisation, which includes the stage of the mind aware of the breathing from abdomen to nose-tip

176. And here both the gross and subtle state and also [progressive]
tranquilizing should be understood. For previously, at the time when the bhikkhu
has still not discerned [the meditation subject], his body and his mind are
disturbed and so they are gross. And while the grossness of the body and the
mind has still not subsided the in-breaths and out-breaths are gross. They get
stronger; his nostrils become inadequate, and he keeps breathing in and out
through his mouth. But they become quiet and still when his body and mind
have been discerned. When they are still then the in-breaths and out-breaths
occur so subtly that he has to investigate whether they exist or not.

189. Here are the stages in giving attention to it: (1) counting, (2) connection,
(3) touching, (4) fixing, (5) observing, (6) turning away, (7) purification, and (8)
looking back on these.

Herein, counting is just counting, connection is carrying on, touching is the
place touched [by the breaths], fixing is absorption, observing is insight, turning
away is the path, purification is fruition, looking back on these is reviewing.

197. The navel is the beginning of the wind issuing out, the heart is its middle
and the nose-tip is its end. The nose-tip is the beginning of the wind entering in,
the heart is its middle and the navel is its end. And if he follows after that, his
mind is distracted by disquiet and perturbation according as it is said: “When
he goes in with mindfulness after the beginning, middle, and end of the in breath,
his mind being distracted internally, both his body and his mind are
disquieted and perturbed and shaky."

Then, fixing his mind on the place normally touched [by the breaths], he should
proceed to give his attention to that.

210. These in-breaths and out-breaths occur striking the tip of the nose in a
long-nosed man and the upper lip in a short-nosed man. So he should fix
the sign thus: “This is the place where they strike.”

204. When someone gives his attention to this meditation subject, sometimes it
is not long before the sign arises in him, and then the fixing, in other words,
absorption adorned with the rest of the jhána factors, is achieved.

so, due to its instruction of Wrong Concentration, the Vissuddhimagga makes the following eroneous statements in relation to Step 3 and the 1st Tetrad:

When they are still then the in-breaths and out-breaths
occur so subtly that he has to investigate whether they exist or not.

When he goes in with mindfulness after the beginning, middle, and end of the in breath,
his mind being distracted internally, both his body and his mind are disquieted and perturbed and shaky.

186. The first tetrad is set forth as a meditation subject for a beginner; but the
other three tetrads are [respectively] set forth as the contemplations of feeling, of
[the manner of] consciousness, and of mental objects, for one who has already
attained jhána in this tetrad.

when the Right Concentration is established, it is not required to investigate the subtle in-breaths and out-breaths as to whether they exist or not

when the Right Concentration is established, the natural awareness of the beginning, middle, and end of the does not disquieten, perturb and shake the mind because the mind is established in the stillness & freedom of vossaga

when the Right Concentration is established, steps 3 and 4 are not for the beginner but are actually fruition of higher training

the Anapanasati Sutta starts each of the last 14 steps with the words: "He trains himself", thus accords each of them similar status

if not for steps 3 & 4, how could vipassana (insight) into the impermanence, unsatisfactoriness & not-self of in-breaths and out-breaths (and the body) occur?