Thats the reason I played devils advocate H. In a previous thread some of the boffins were saying its impossible to get isomerisation but I do know that alright it was not a true experiment but when I have done low temp Whirlpooling with no other additions you do get some bitterness and thats where the perceived bitterness argument started saying it was impossible for isomerisation.You do get isomerisation at lower temperatures, down to about 40C I believe but the rate of isomerisation drops dramatically so for all practical purposes below 60C (4%) can be ignored.
Well I am not a full blown boffin and do listen to some of them as you can get some good info but who do you believe.
I will in summing up add that I am susceptible to tasting bitterness more than most and thats why I have gone down that route of doing a lot of whirlpooling but do standard additions in Bitters/Ales. As you have said for most brewers it is not worth even bothering about at the lower end but as you have pointed out at the higher end of whirlpooling you can get some serious IBU contribution when adding masses of High AA hops.
Personally I think the info on this thread as been good and stands well with what I believe just hope this helps some of the newer members