NestWhile::nres
NestWhileList::nres
An error occurs because the number of elements that are computed is less than the position specified by the sixth argument:
NestWhileList[(# + 1)&, 5, (# < 10)&, 1, 5, -10]This shows a valid use of the sixth argument in NestWhileList:
NestWhileList[(# + 1)&, 5, (# < 10)&, 1, 5, -4]