[Balanor]

Though, at lvl 10 RDD your race switches to Half-Dragon, does it not?

I stand corrected. I looked at the description and even on the wiki site it says they are considered a half-dragon at level 10 RDD. Game mechanics-wise, I'm pretty sure nothing happens though - your race isn't changed and nothing gets added to your subrace (at least from what is standard for RDD in NWN). So long as the base race doesn't change or the subrace doesn't change for the PC to indicate a change in the race, you're OK. Maybe test it out in a character builder module sometime to see if anything actually changes with either when you reach level 10 RDD just to be sure though.