The affix yat comes in the prakkritīya senses after the word kambala, when a Name is meant.,
This debars 'chha'. Thus कम्बल + यत् = कम्बल्यं 'A kambalya-measure of wool' = 100 Palas of wool. This is the name of a measure, such as कम्बल्यमूर्णा पलशतम् ॥
Why do we say संज्ञायां? Observe कम्बलीया ऊर्णा \wool\ lit. 'fit for making blanket', which is formed by छ ॥,