Exactly! It was a pretty cool experiment.

 

when i had my gas truck made alot of trips to wva 200.3 miles each way .checked milage all the time. before hard cover ave. 16.8 with hard coverave.18.2 went to soft coverwas 17.3. that was summer or winter all interstate at 68 mph. with with diesel so far 18.2 and its stock with no cover yet going to put tri-fold hard cover on this one easy access and easy off.

 

That sounds exactly like what I would think it would be.