ericdan
your experience matches mine both for color film and for black and white
(there was a url link here which no longer exists)
about halfway through the thread you will see information posted by a appugger named "mr bill"
he worked for a major portrait company and he and his workmates did all sorts of "destructive testing"
on color film ( "hot box" ). it was interesting to see that color films are quite robust and they did not degrade
as one might imagine they would.
me, personally i only shoot expired film these days, some old, some very old, and while i don't use a densitometer
(and don't care to use one ) i haven't found much trouble in my expired emulsions. YMMV thought, because
others in the thread posted their findings ( B/W ) from using a densitometer, and posted #'s but even after they were
asked what the numbers meant their meanings were never revealed ... so my guess is that "there was a little fog" ...
and too much for their taste?
as for your provia ( i have about 300+ sheets at room temperature as well ) it might suffer a little contrast loss? maybe a little speed loss
and maybe a little color shift ... i'm processing all mine in b/w so i rate it slow ( way less than half box speed )
and processing it in dilute print developer first and then coffee developer.
good luck
john