[gone-ot]

...here's my definite maybe answer: "probably" yes because you'd "probably" shift engine rpm closer into its 'best' BSFC area, which "probably" would lower its fuel consumption; however, it could "probably" mean that hills & high winds might "probably" become too much of a load and force you to either (a) apply more throttle (more fuel) or down shift (more rpm)--both of which will increase fuel consumption.

...don't you just love "weaseley-worded" answers?!?!