I don't know if this will clarify or obfuscate matters, but I was inclined to parse the second phrase in PD19.
ἐάν τις αὐτῆς τὰ πέρατα καταμετρήσῃ τῷ λογισμῷ.
ἐάν = if
Both τις and αὐτῆς are feminine singular which, to me, seems to refer back to τὴν ἡδονὴν (pleasure) from the previous phrase which is also feminine.
τὰ πέρατα we've mentioned are "the limits" but, more precisely, defined as "end, limit, boundary"
Henry George Liddell, Robert Scott, A Greek-English Lexicon, πέρα^ς
In philosophy, a πέρας (singular) can refer to "the perfection" of something. LSJ gives cites including one to P.Herc 831.8 https://papyri.info/dclp/59491
which brings us to a dative construction in the last three words:
καταμετρήσῃ τῷ λογισμῷ
I find the idea of the "boundary" interesting in light of καταμετρήσῃ (noun singular feminine dative) "measuring out" from the verb καταμετρέω
Henry George Liddell, Robert Scott, A Greek-English Lexicon, καταμετρ-έω
...which could just mean "measure out" but could also refer to laying out a camp ("castrametation" a word I never read before), i.e., measuring out the area of an encampment or "assigning land held by military tenure." Joshua may find this interesting from a surveying perspective.
Finally, we come to τῷ λογισμῷ "to logismoi"
The basic definition of λογισμός "logismos" is "counting, calculation" or simply "calculation or reasoning" if not associated with numbers.
This is related to λόγος "logos" which is notoriously tricky to parse (and is even used to refer to Jesus as part of the Trinity "Ho Logos" "The Word"). Check out the LSJ definition:
Henry George Liddell, Robert Scott, A Greek-English Lexicon, λόγος
So, at its most basic, "to logismoi" could be parsed "by using one's logos" which puts us right back into the "notoriously tricky" parsing of what logos means. Reasoning is acceptable, but it carried a lot more connotations in ancient Greek. Hence my hobby horse/soap box about translators feeling they have to reduce complex connotations to one simple English word with its own linguistic baggage.
So, an alternative translation of the second phrase of PD19, *could* be:
"if pleasure (is) being measured out through the logos."
Take that for what its worth. LOL. You were expected clarity?
PS. I found that the prefix κατα- kata- in a word like καταμετρήσῃ katametrēsēi (kata + metrēsēi) can convey "fully, completely". metrēsēi is related to English meter, measure, etc. So we're getting a phrase that conveys something like measuring out or laying out the boundaries or limits fully and completely through the use of our reasoning powers, to fully understanding how pleasure impacts our life and not accepting a popular notion of the hoi polloi that pleasure is insatiable and expands infinitely, we must understand and internalize that pleasure has limits and boundaries that can be understood.
