I've found that vinegar can help cut the bitterness that can come from ancho chili powder, but there's not much chili powder at 1/2 tsp vs. 6 tbsp of vinegar.

That recipe reads 'cloyingly sweet' to me. There are essentially 3 cups of sugar to traces of seasonings + 1/2 cup of ketchup that also has quite a bit of sugar. But that's just my opinion.