-vada / -vadin

[jonathan silk]

I recently "corrected" the draft of a friend's paper, and suggested that
the usage Sarvastivada was correct for the sect, and Sarvastivadin for a
follower of said sect. The same for Vibhajyavadin. However, in looking
through some sources my friend tells me that the actual usage in texts
seems to be inconsistent. Is this possible, grammatically speaking?  In
other words, can we take 'Sarvastivadin' as the name of the sect and
'Sarvastivada' is an adjective form (as the 'Mulasarvastivada-vinaya')?
Apparently both Frauwallner and Bareau use Sarvastivadin as the name of the
sect.

Any comments welcome!

Jonathan Silk
SILK at wmich.edu