notes on the Dhamma: Dhamma-vicaya-sambojjhanga of 7sb and the 4th category of 4sp, Dhamma-anu-passsana, are one and the same

Is this commonly known?

I've suspected this for years, but only recently became thoroughly convinced.

Dhamma-vicaya and Dhamma-anupasssana at first glance seem to have different roles and functions.

Let's look at some parallel examples, so you get a sense of how much latitude may be expected when two terms/concepts at first seem to be different,

SN 48.9 paṭhama-vibhaṅga-suttaṃ

No one would question that sati-indriya (of 5 indriya and 5 bala) is exactly the same as samma-sati (of 8aam) and 4sp (satipatttana), and sati-sambojjhanga (of 7sb).
But read the sati-indriya definition carefully in SN 48.9, it's very different than samma sati and 4sp definition.

SN 48.9 (3. Sati: Rememberness)

♦ “katamañ-ca, bhikkhave, sat-indriyaṃ?	"{And}-what, monks, (is) rememberness-faculty?
idha, bhikkhave, ariya-sāvako	Here, monks, (a) disciple-of-the-noble-ones,
satimā hoti	{is} rememberful,
paramena sati-nepakkena samannāgato	supreme rememberness-(and)-prudence (he) possesses,
cira-katampi cira-bhāsitampi	(what was) {done}-long-ago, {spoken}-long-ago,
saritā anussaritā —	(he) remembers (and) recollects -
idaṃ vuccati, bhikkhave, sat-indriyaṃ.	this (is) called, *********, rememberness-faculty.

Similarly, with samadhi-indriya STED definition in SN 48.9, and samma-samadhi definition of 4 jhanas. Each definition is giving you more information not found in the other.

SN 48.9 (4. Samādhi: Undistractable-lucidity)

♦ “katamañ-ca, bhikkhave, samādh-indriyaṃ?	"{And}-what, monks, (is) undistractable-lucidity-faculty?
idha, bhikkhave, ariya-sāvako	Here, monks, (a) disciple-of-the-noble-ones,
vossagg-ārammaṇaṃ karitvā	{having made} release-(as the)-object
labhati samādhiṃ,	(he) obtains undistractable-lucidity,
labhati cittassa ekaggataṃ —	(he) obtains mind’s singularity -
idaṃ vuccati, bhikkhave, samādh-indriyaṃ.	this (is) called, *********, undistractable-lucidity-faculty.

Similarly with samadhi-sambojjhanga and samma-samadhi. At first it's not clear just how much they overlap, but after researching carefully, you'll find both explicitly are tied to 4 jhanas.

With viriya-indriya (in SN 48.9) and samma-vayamo, they overlap with similar information, but still the indriya version offers some important information not contained in samm-vayamo and samma-padhana.

SN 48.9 (2. Vīriya: Vigor)

♦ “katamañ-ca, bhikkhave, vīriy-indriyaṃ?	"{and}-what, monks, (is) vigor-faculty?
idha, bhikkhave, ariya-sāvako	here, monks, (a) disciple-of-the-noble-ones
āraddha-vīriyo viharati	(with) aroused-vigor (he) dwells,
a-kusalānaṃ dhammānaṃ pahānāya,	(for) un-skillful qualities removal,
kusalānaṃ dhammānaṃ upasampadāya,	(for) skillful qualities undertaking,
thāmavā daḷha-parakkamo	(He is) powerful, strong-(in)-exertion,
a-nikkhitta-dhuro	not-neglecting-duties
kusalesu dhammesu —	(in) [developing] skillful-qualities -
idaṃ vuccati, bhikkhave, vīriy-indriyaṃ.	this (is) called, *********, vigor-faculty.

So what I realized is that this is the same thing going on with Dhamma-vicaya-sambojjhanga, and the 4th category Dhamma in 4sp. Even though at first they seem to be different function, different roles, because each contains some information not appearing in the other, but as with the parallel cases above, that's precisely why they contain different information, it's to expand on the role and function of the quality in question.