steady on BelArgUsa
Now you're comparing two different spec sheets. GE and CFM tend to be 1-2% better in cruise than their R-R and PW rivals but this is not dramatic enough sales-speak. The engine burn at sfc 0.35 lb/lb-hr is from a spec sheet for sea level static take-off conditions. The other figure is 0.58lb/lb-hr in cruise mach 0.8 at F350. The original DC-9 engines were much nearer an sfc of 0.8 in cruise. So the money saved is from figures 0.8 bad, 0.58 good.
Please don't fall into the salesman's trap of thinking there are engines that have an sfc of 0.35 in cruise. Apples and Oranges.
There will be a flight level, speed and load condition for any engine airframe combination that produces the best sfc figure. There is an engineering tool called Buckingham's Pi-Theorem which salesmen hijack to bat their eyelids with at prospective customers. I'd call it finding a ruse to put your products in the best possible light at the expense of your opponents and hoping that no-one will notice.
Cheers