6k an hour is way too high. Sure Hajj customers pay those prices but only because operators just don't have that kind of lift sitting around. I allways thought doing Hajj runs at WOA was bad for business because we would dump on regular customers for some quick cash.
I would have to agree with the 3.5k to 4.5k for a moderate to long term lease, might get away with it on a short term lease if the operator has excess lift sitting around. The difference in price is equal to the operating cost of the aircraft fuel/seat or fuel/pound.