All i would say is i wanted a small yorkie and my Pippa ended up being 8lb (I thought she would be 5 - 6 lb) she is still small but heavy.
But i couldn't care less now, she is my best friend and i never got her to breed or show so it doesn't matter.
If your boy is gonna be your pet and not for breeding purposes/showing then who cares how much he'll weigh, he still be your yorkie
and you can love him regardless of weight.
Whats a couple of pound here or there??