Yes, sure, in the middle east? if you fly the LJ60 as all the americans I know over there then I understand why you use 250kts.... use 275 .73M and you will make it faster to FL390, books also say range on the LJ60 is 2.800 miles and FL510, have you ever been close to those figures? I do not and I have a bunch of hours on the 60, of course in europe....