Brahma Sutras are divided into Adhikaranas Or topics each dealing with a particular part of the philosophy.
The Adhikaranas have one or more sutras. Purvapaksha sutras are the opinions of the objector to the Brahma Sutras and Siddhannta sutras are sutras expressing the opinion of the Sutrakara which represents the opinion of the Brahma Sutras. Each Adhikarana needs to be established before another Adhikarana starts.
Now an Adhikarana can sometimes have only one sutra. For example Jignsathvadhikarana Or Janmadyasyadhikarana. They have only one sutra. This has to be a Siddhanta sutra as it needs to be established.
Rule 1: If there is only sutra in an Adhikarana then it has to be a Siddhanta Sutra(S)
Jijnasadhikaranam: Topic 1 (Sutra 1) - S Janmadyadhikaranam: Topic 2 (Sutra 2) - S
As Adhikarana needs to be established before starting another Adhikarana, the last sutra of an Adhikarana has to be Siddhanta Sutra
Rule 2: The last sutra of any Adhikarana has to be a Siddhanta sutra(S)
Ikshatyadyadhikaranam: Topic 5 (Sutras 5-11) - SSSSSSS
Pratardanadhikaranam: Topic 11 (Sutras 28-31) - SSSS
Now, normally the Sutras are mainly Siddhanta sutras, but once in a while we will get Purvapaksha Sutras(P), which by rule cannot be the last sutra of a particular Adhikarana
So the Adhikarana can either have Purvapaksha sandwiched in between or start with Purvapaksha and end with Siddhanta. So we have two basic patterns one starts with Purvapaksha sutra or has Purvapaksha sutra in between. So either
Partern 1: SSPPPSS, SSPPSSPSS or
Pattern 2: PPSS, PPSSPSS
Now, the main question is, whenever commentators are commenting on Adhikaranas with Purvapaksha sutra, do they use a consistent pattern in their entire bhashya or do they use different patterns for different Adhikaranas with Purvapaksha sutra?
How many Adhikaranas with Purvapaksha sutras are there? Which all commentators use which which pattern how many times? Do they use them consistently?
For answering this, we can consider Advaita, Vishishitdvaita and Dvaita.
P.S: This question requires lots of analysis and effort to answer, so if anyone can offer some bounty for this question, it would be greatly appreciated. Thank you.