Questions on Seller Concessions

[James Edwards]

So I've been researching seller concessions, either closing costs, or paid points. 

It appears at 10% down, max seller can do is 3% on Fanny Freddy loans. 

I am curious if there would be any creative work arounds?  Is it the full amount a seller can comp, or is that just the closing costs limit and seller can do other things? 

Ie say I want a home backup generator, or central air installed and offer is contingent on that. I would imagine most sellers would just comp the value. Does that eat into the max the seller could do?