was it two whole for a total of 15#?
Then those two cut into 8 total pieces?
How hot are you running......that could be accurate if they're small pieces, but stuff like this actually cooks better in a somewhat larger piece......
also, check where your therm is......is it too far into a chunk, then reading closer to the outer edge which will give a slightly false reading....or right up next to a bone, which can also fool the therm.............
If they're cut to a thinner overall piece than the original, it will be faster, but the real goodness comes from the chemical changeover @ 165~180f......should dwell for a time in temp, then rise fairly rapidly......
I have to go, but hopefully others will pitch some guidance here......