OP, here's another approach (the one I use for APA, AIPA) : Add your 65 IBUs for 60 mins using Columbus (for IPA), and add all of your would-be boil additions post boil, after cooling to 175F for a hop stand. Stir well every few minutes for 30 minutes then finish cooling. You'll get nice flavor and aroma, and whatever IBUs calculate from this are not really noticeable to your palate. Then double the dry hops.