Advocate:
"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."
Yes it would. The point i was trying to raise is that by deliberately entering a slightly aft C of G & then using the FMC computed trim setting, the stabiliser would then be set up for a more aft C of G than actually exists. In so doing, minimise any probability of the nose rotating prematurely.
But I am persuaded by JTs point, essentially that the difference is too minute to be noticed anyway.