I had spray foam sprayed in between rafters.  Part of it ended up lower than I expected so they came back and filled in that and a few low spots.  There was a low spot they missed in the corner of the roof, ended up with maybe 3 in instead of 5+ over a few square feet.  Don’t think I want to call them back over that, I’ve had enough.  Can I fill this in myself with a can of osi quad foam and a gun or is that just going to be a disaster?  Does it even matter when I have rafters every 16 feet?  Will it just melt the frost off faster on a cold morning?