Classifications of prescriptions: Mīmāṃsakas get organized

At first, I have been looking for a comprehensive classification of prescriptions in Mīmāṃsā and got irritated by the simultaneous presence of what seemed to me as competing classifications. Later on, I realised that these various classifications originated out of specific exegetic concerns. All of them have been included into inclusive classifications due to the Mīmāṃsaka (and Indian) inclination to classify whatever possible. These classifications differ from the ones presupposed in Dharmasūtra/Grammar, etc., as far as I understand, also because of the stress laid on the common vidhi-nature of all their elements. Then, among post-Maṇḍana authors, vidhi has been regarded as an important category in itself and in certain cases one started to classify vidhis departing from a different point of view, that is investigating the nature of vidhi itself, independent of a specific textual passage to be interpreted. In other words, pre-Maṇḍana authors identified single instances and collected them all together as vidhis. Some post-Maṇḍana (and especially later) authors, instead, could have started to aim at understanding the vidhisvarūpa ("own nature of prescription") and to see classifications as explaining it. This shift is not completed in any of the texts (even later ones) I am aware of, which all explain vidhitattva (the "essence of prescription") without mentioning the types of vidhis and insert instead classifications among exegetical topics. Maṇḍana himself seem to 'use' the classifications he was aware of, and not to understand them as pointing out the nature of vidhi (which, instead, is explained by him as the fact that the action prescribed is the instrument to achieve a desired result, iṣṭasādhanatva).