Praudhamanorama p22

p22

[On] 'here': the meaning is 'only here'. [On] 'even though': the purport is because the rule of inclusion has not yet been established. 'ho ḍhaḥ' (P. 8.2.31) is an illustrative indication: it should be understood that retroflexion does not apply in 'ramāsu', the substitution of 'gh' for 'ā' by 'jhayo ho'nyatarasyām' (P. 8.4.62) does not apply in 'vāgaśīḥ', and the substitution of 'gh' by 'dāderdhātorghaḥ' (P. 8.2.32) does not apply in 'dāsīṣṭa' and so forth. If, however, one explains a difference in effort by continuing 'īṣat' (slightly) into 'vivṛtamūṣmaṇām' (the open is of the spirants) and ending its continuation in 'svarāṇāṃ ca' (and of the vowels), then the rule 'nājjhalau' is not needed, as established in the Mahābhāṣya.
'vṛddhirādaic' (P. 1.1.1). Here 'aic' has only two morae, because it is followed by the letter 't'. Therefore, in 'kṛṣṇaikatvam', a three-mora vowel does not arise. So too in the next rule; therefore, in 'gaṅgodakam' and so forth, a three-mora vowel does not arise.