The insidies of an adverb: mātra

I already dedicated a post to Sanskrit Syntax. In this one I shall focus on the word mātra. At the end of a compound, where it is mostly found, this can mean either "generally" or "only".
For instance,
1. Rāmānujācārya, in his Tantrarahasya, forth book, states that the exhortative suffixes (liṅādipratyaya) designate kāryamātra, that is, "what has to be done in general", whereas one automatically adds to it the further connotation of being an instrument apt to realise a desired result.
2. Mahādeva Vedāntin, in his Mīmāṃsānyāyasaṅgraha (wonderfully edited for the first time by Jim Benson) states that the suffix -tvā in gerunds means pūrvakālamātra, that is, "only a previous time [and nothing else]", thus implicitly pointing out that it does not express an immediate sequence (the finite verb connected to the gerund needs not express an action taking place immediately after that of the gerund; it is enough for it to take place sometime after it).

There are, unluckly enough, also controversial cases, such as the following one (from Mīmāmṣānyāyasaṅgraha, 1.1.3, p. 52 in Benson's edition), where an objector states that there is no point in investingating on the means of knowledge (direct perception, inference, etc.):

mānamātreṇa meyasiddher na parīkṣyaṃ mānam

The latter part certainly means: "Because the knowable objects are established, the means of knowledge should not be investigated upon". But through what are the knowable objects established? Either "through the means of knowledge only" or "through the means of knowledge in general". In the first case, the whole sentence would mean that, since there is no other access to the knowable objects, there is no point in investigating on the means of knowledge and I personally tend to favour this interpretation. However, the learned editor and translator of this work, proposes, instead, the following translation: "Since all the objects of valid knowledge are established by the means of valid knowledge generally, the means need not be examined (here)". And explains the "generally" in a footnote: "I.e., anything that is recongnized as a means of valid knowledge serves to establish the existence of objwcts of valid knowledge. This includes vedic injunctions and prohibitions" (p. 327).