Regarding fuel numbers for E175 vs CR9....

I don't think the fuel burn numbers are all that different for the same altitude, I think the biggest difference is that E175s are consistently flying at lower altitudes than CR9s. For a takeoff at max gross we can only go up to FL300 or so initially! It's fairly seldom that I have the numbers to get above FL360. From what CR9 drivers tell me, they operate routinely in the mid to high 30s. There's a big difference in fuel burn between 300 and 370.

It's not that the E175 doesn't have the power to get up to a decent cruise altitude, I'm usually still doing 700-800 fpm when I reach the book's max altitude number. The wing may be more of a limiting factor...at max cruise alt you're definitely seeing a good bit of the yellow speed tape. Still, I think the numbers in the book are pretty conservative and higher altitudes could be used safely in smooth air. If there's really a 20-30% disparity in fuel burn between the E175 and CR9 I suspect our management will be pressing Embraer to rework those numbers.