After a numeral, the first vowel of saṃvatsara and of a numeral, gets vṛddhi before a taddhita affix having an indicatory ñ , ṇ or k ,
Thus द्विसांवत्सरिकः = द्वौ संवत्सरावधीष्टो भृतो भूतो or भावी 5.1.80, त्रिसांवत्सरिकः, द्विषाष्ठिकः = द्वे षष्टी अधीष्टो भृतो भूतो भावी वा ॥ The words द्वि, षष्टी &c when applied to वर्ष 7.3.16 and Numerals give rise to the affixes taught under kaladhikara 5.1.78 — 5.1.97. The special mention of संवत्सर here, (though this is a परिमाण word and would have been included in the sutra 7.3.17) implies that the word परिमाण in that sutra does not mean the measure of time, but a measure of any other thing than time. Therefore, with other time-words than samvatsara, the Vriddhi takes place in the regular way: as द्वैसमिकः, त्रैसमिकः ॥ Similarly in sutra 4.1.22, the word परिमाण does not mean the measure of time or numerals, as त्रिवर्षा, द्विवर्षा माणविका ॥ In short, the word परिमाण in these sutras (and elsewhere 3.2.23, 2.3.46 &c.) means \mass or bulk\, and not a measure in general.,