Unless it has something to do with a previous version of PBP, can't say.
But this simple program comes up with 248 (-8). PBP 2.46
Code:
 @  __CONFIG    _CONFIG1H, _OSCS_OFF_1H & _HS_OSC_1H
define OSC 20
clear

remaining var byte
rows      var byte

rows = 8
remaining = -rows

stop
Something you might try is ...

remaining = 0 - rows