IBUs and Wort Cooling time

I cool my wort in an ice bath in the sink. Takes a while for me to get down to 70-80. About an hour.

I've been noticing my beers are more bitter than I bargain for using promash or other software.

Could the long cooling time be increasing my IBUs?

If so, if I move my 15 min additions to 5 min. Would I still get the flavor and aroma or would I be decreasing flavor and increasing aroma considerably?

Any suggestions?

It won't increase your IBUs significantly. It's more likely your hop variety or water chemistry that is producing the harsh taste. Try a neutral bittering hop like Warrior, Magnum or Horizon (careful, a little goes a long way), consider first wort hopping, and adjust your water chemistry to style.