Calculating IBU's for hops at flameout

[Showdown]

Is there a way of calculating IBU additions in Brewers Friend for the addition of hops at flame-out? For instance, I toss in a few oz of hops at flame-out, cover and let sit for 15-20 minutes before cooling and pitching. Besides aroma, there should be a significant bump in IBU based on the temps staying hot, but I don't have a rolling boil going on so I'm not sure if I plug it in as a whirlpool add or just an aroma add. If it's a whirlpool add, what is utilization percentage?

 

[masskrug]

Subscribing. I just toss them in with the wort chiller for 30 minutes and label them as. "Aroma" hops.

 

[Smellyglove]

In beersmith at least the default utilization factor is 50% if added to 194F, comparing to utilization while boiling. I'm not sure about this, but it might be that it reckons you're cooling the wort. This is WP-addition.

 

[Showdown]

Brewers Friend recommends 10% utilization, or even zero. Seems like there is a huge discrepency without much info on actual contribution.

 

[pablosbrewing]

Full boil utilization is about 35%, whirlpool is about 10% from this BYO article on hopstands:

https://byo.com/hops/item/2808-hop-stands