The first one is part of the break in period. You drain and fill to remove any shavings the ring and pinion had during break-in.
Better late then never. May want to change it again in 5k just to be sure you got everything out. But then again, really, how many people actually do this? Besides myself I can only think of a handfull of people who buy new and stick to the manufactures recomendations for break-in.
Also do yourself a favor and use Synthetic gear lube. The drain plug on the XL7 is magnetic so most if anything is cought by that.