From everything I've read, the typical stall temp for a pork butt is around 160. Mine leveled out at 147. Then, went down to 142. Been there a while, now. I pulled the platesetter, stirred up the lump and added a bit more since the dome temp started to fall. Replaced platesetter, put the pork back on, and dome is back at 300, grid temp is 315. Meat is at 142.
The dip in temp isn't a huge concern, but that seems pretty low for a stall.
LBGE since June 2012