If the tranny does not have the "lifetime fluid", I would consider a complete fluid change and filter change. I did this to the 530 I had previous to my current 535. I don't recall any rough shifts but it did shift firm when under hard accelleration.
I had my trans done at a shop that unhooks the ATF cooler at the radiator and flushes something like 15 quarts of fluid plus changing the filter. I felt like it was pretty good insurance.
If you have a "lifetime fluid" trans, you pay about $300 for the fluid and that covers just what is dumped when the pan comes off to change the filter.
Mike