aspinwing. Your example may well work in Canada and certain lumpier, sunnier parts of Europe but it certainly doesnt in the UK. +25 at 3000' and +31 at MSL? Might get that about two days a year if we're lucky. Most of the time we wont even be able to reach 3000' due to cloud cover!
Given that our climate is reasonably stable (= usually cr@p) then loading the heli up to a high gross weight is the only real variable we have to play with.