Adjust Flamout Hop Addition for Counterflow Chiller

Just brewed a clone of Russian Rivers Hill 2 Row 56 Pale Ale and it called for a flameout addition of 1oz of Simcoe.
Using Beersmith calculated it should steep for 10mins to reach the proper IBU extraction and then I started to run the wort through my counterflow chiller which took about 20mins.
I never thought about it until then, shouldn't I have plugged that addition in Beersmith at 20 instead of 10mins since the wort in the kettle is still around 200degrees and there is still alpha acid isomerization going on and just started running it through the chiller as soon as I added the hops and not let it sit first?
It would increase the IBUs and possibly effect the aroma from that last addition, or not?
Thoughts?

Although I know how bittering and aroma are achieved, I'm not an expert on the science of IBU extractions. I plug the additions into my software and it tells me how much I need for what I want to achieve. I never count anything after flame out. If the hops are added at flameout, its for aroma. I don't know what your full recipe was but in my opinion if the recipe has a hop addition at flame out and my software indicates the IBU's are low, you increase the earlier hop additions to get the IBU's where they need to be, not hops to raise that are supposed to be added at flame out t raise your IBU's. Using your example in trying to determine IBU extraction as some wort is sitting in your kettle (not boiling any longer) while some is being cooled (not really extracting IBU's) it would be very hard to determine the exact IBU extraction difference. I believe it would be miniscule at best.