Sorry I don't think I am explaining what I am getting at. What I am trying to say my current opinion (possibly incorrect) is that whatever a 30 min addition does you could get the same result using less hops by mixing this addition between a 60 min and a later addition, do you disagree?
Personally I never bother with a 30 min addition, but on the podcast I linked earlier in the thread they made 3 beers, identical other than 1 had just a 60min addition, 1 just a 30 min addition and 1 a flame out addition.
The testers (pro-brewers IIRC) not only found it surprising hard to tell the beers apart, but when blending the beers togther found adding the 30min beer to the other 2 added a 'roundness' that wasn't there with just the early & late additions. Its worth a listen