Dear Martin, have you considered the possibility that the sign you read as u at the end is A) in fact a virāma; or B) a scribal error for what was meant to be a virāma? Given that it is a north Indian manuscript, a Telugu-ish ending seems unlikely as you say. I am sure I have seen "saṃvat" written (on a copper plate in Nagari) with a virāma that looked very much like an u. I have no particular recollection of ever seeing saṃmat instead of saṃvat, but it saṃmat would not be a strange development.Daniel