At what weight? Max gross? Remember that the CRJ550 won’t weigh the same as the CRJ700. So it won’t burn as much gas.
Good point. 200 with 50 pax (and associated ballast), fuel for 600nm @ M.72 FL330 2400 pph.
700 with 70 pax, fuel for 600nm @ M.78 FL370 3400pph.
Remove 20 pax and 20 seats and 1 FA. Add a couple closets, coke machine, upgrade 4 seats. Probably = 5000 lbs lower cruise weight, fuel burn drops to 3300 pph. Climb to F390 save another 100pph.