Mainjafad,
I see!
If it helps (but in no way trying to detract from the writer's licence!):The 6600 lbs of fuel in the T4 would have given you 5800 until you needed to be in the landing environment, which at about 120 lbs per minute for 420 kts would give you a total range from tanker to hover/ crash of about 340 miles.
You could (as you say) profit from going high I think the high level bingo calculation was something like 1200 plus ten pounds per mile.