The siddhāntin's view seems to be the latter, since Pārthasārathi himself asks (as any reader would have done): "But isn't it the case that the bhāvanā is exactly the general form common to verbal roots' meanings?" (nanv evaṃ dhātvarthasāmānyam eva bhāvanā syāt). The answer is no (neti brūmaḥ), "since the bhāvanā is different according to every single verbal root" (vilakṣaṇatvāt pratidhātvartham). In fact, a different bhāvanā is involved in cooking or in walking (anyad dhi pākasyaodanaṃ praty anukūlyam anyac ca calanādeḥ saṃyogādi prati, phalabhedāt).
But the answer does not address the more general point of the link between the bhāvanā and the verbal root's meaning. A bhāvanā specific to every verbal root may still be closely related to it. Luckily enough, Pārthasārathi adds a further argument. This claims that since the same thing (e.g. "decision") can be expressed by a verbal ending (as usually the case) or by a verbal root ("to decide", saṅkalp-), the bhāvanā cannot be the general form present in all verbal roots.
Even in this case, what one understands is that Pārthasārathi disagrees with the idea that a bhāvanā expresses an action in general (so to say, the general form of the action, the sāmānya) and that the verbal root connected to it expresses the specific action at stake in that case (the viśeṣa). So, Frauwallner is wrong in maintaining that Pārthasārathi totally agrees with Kumārila ("schon diese kurze Wiedergabe zeigt deutlich, daß sich Pārthasārathi bei seiner Behandlung der bhāvanā in den Grundzügen aufs stärkste an Kumārila anlehnt" Frauwallner 1938: S.245), since the latter explains the relation of bhāvanā and verbal root as one of universal/particular.
Finally, Pārthasārathi concludes "hence, it is established that the bhāvanā is different from the meaning of the verbal root" (tasmāt siddhaṃ dhātvarthātiriktaṃ bhāvanārūpam). Hence, the meaning of the verbal root is (just) the instrument of this bhāvanā (tatra ca dhātvarthaḥ karaṇam). Out of it is the apūrva also postulated (tato 'pūrvaṃ kalpyate).