You did the right thing asking here, then calling them, they they are doing the right thing coming back out to do it again. It's a very simple and fast process for them, it is worth it to them to keep your business so kudos to them.
The obvious issue with the leaves is that you want a uniform distribution of the overseeded seeds. And the leaves throws in a variable there that pretty much guarantees that not happening. A big pile of leaves has seed on top of it, wind and whatever else may blow them elsewhere and beneath you have no seeds.