I'd agree with j_t on this in that it should not matter about rounding up or down, the figures are so little it will have un-noticible effect during rotation.
Also on the 737 NG that I fly, the FMC will accept CofG to one decimal place, plus after it calculates a stab trim, most people I fly with would only use that figure to check it's almost the same as the figure given on the loadsheet, but would in fact trim the aircraft to the loadsheet trim given.
If I have this correct in my head gengis, rounding it upwards, you would be moving the CofG towards the tail and therefor increasing the likelihood of the nose rotating.
Somebody correct on this if i'm wrong, i'm just picturing a trim sheet in my head
