Arthabhāvanā in Bhāṭṭacintāmaṇi

In Kevalānandasaraswatī's (sic) impressing Mīmāṃsākoṣa the following explanation can be found:

arthabhāvanā … arthātmatvaṃ arthaviṣayatvaṃ arthāśritatvaṃ vā. tathā ca arthaniṣṭhatvād arthabhāvanā phalotpattyanukūlakṛtinodanādivyāpārarūpā ākhyātatvāvacchinnaśakyā cetanācetanakartṛsādharaṇī kartṛśaktiḥ (gāgābhaṭṭa's bhāṭṭacintāmaṇi p. 90-91). 

that is (I am not translating artha, since its meaning in this connection is exactly what I am trying to understand):

arthabhāvanā [is] the fact of having an artha as its essence, as its content or as its support. In this way, since it rests on an artha, the arthabhāvanā is the potentiality of a doer, which is common to conscious and non conscious doers, liable to be determined by verbal endings [but why -tva?], having the form of an activity such as impelling and being and action favorable to the arousal of the result.

Which does not solve the problem of its name. Then, the author of the Koṣa quotes many other authorities (Kumārila, Bhaṭṭa Śaṅkara, Somanātha's commentary “Mayūkhamālikā” ad Pārthasārathi Miśra's Śāstradīpikā). Most of them do not talk at all about the etymological meaning of artha in arthabhāvanā. The longest discussions on arthabhāvanā in general are to be found, according to the Koṣa, in Gāgābhaṭṭa's Mīmāṃsācintāmaṇi and in Someśvara Bhaṭṭa's Nyȳasudhā (commentary ad TV). The latter also contains an explanation supporting Prof. Kataoka's analysis (see next posts).