The strict adherence to the text makes Mīmāṃsakas distinguish between the expectation of two seemingly identical terms according to what is available around them. In this sense, their analysis is a posteriori, since it accounts for what one sees, rather than fore-seeing what one will get. This a posteriori procedure is probably guided by the Mīmāṃsā focus on an actual text, the Veda.
For instance (see Rāmānujācārya's Tantrarahasya, IV, §10.5), in the case of sacrifices lacking a specific prompted person (niyojya), one has to necessarily postulate one. And this one has to be necessarily specified by a desire (since a person can only be prompted insofar as s/he desires the result mentioned in the prompting sentence). Hence, one postulates a prompted person desiring heaven. In fact, heaven is (as shown in ŚBh) tantamount to happiness and the human kind naturally strives for happiness.
But how does the relation among the prescription's elements take place in the case of a directly mentioned (śruta) prompted person and in the case of a postulated one? Even in the first case, the expectation of a prompted person by the injunction is mediated by the intermediate steps of responsibility and agent-ness. Nonetheless, since the prompted person is directly mentioned, one does not need to get at it through this mediation and s/he is directly related to the injunction. Hence, the relation occurs immediately, without following the sequence of expectation. This also means that expectation is understood as the fact of requiring something, i.e., as a sequential process. If, instead, through proximity (as in this case) or fitness (yogyatā) one immediately gets a complement, the expectation process is not needed to complete the sentence.
On the other hand, when the prompted person is not explicitly mentioned the order of relation follows that of expectation. In fact, in the latter case all three are not directly mentioned and there is hence no proximity to be followed before the expectation takes place.
The responsible- and the doer-stages are hardly ever directly mentioned together with the prompted person. Yet, their presence can be indirectly detected because of its effects. In fact, some prescriptions do not have any prompted person at all (nor do they need any), because the responsibility for their performance is taken over by someone else. For instance, the prescription about the pre-sacrifices does not need a specific prompted person, since the person prompted to the main sacrifice will anyway perform it with all its auxiliaries (see TR IV, §11.5.1). In such cases, the prescription's expectation is appeased through another prompted person once one has reached the level of the responsibility, since the responsibility for the main ritual includes that for the pre-sacrifices, too. And, in fact, these pre-sacrifices are indeed performed (doer-level). This shows that the responsible person is the same.