Just booked September OGG-LHR r.t. $2685 all-in (includes onerous UK front-cabin departure tax) lie-flat all the way. Same fare from LAX,SMF, $1100 more from SFO. Didn't check others, but assume main hubs get the shaft. Mid-week travel summer and into Fall. Best to CDG is an occasional $4100.
Airline pricing
I transit SFO both ways, ride a (currently scheduled) 752 both ways between OGG and SFO, and pay $1100 less for a r.t to LHR than a S.F. originator does.