No one said it does--the OP is simply advocating flying the cost index speeds and taxiing at a safe speed vs. blasting around at .81/.79 for no reason like a dummy.

If you leave as early as possible, taxi at safe speeds per the AIM/GOM/CFM, fly cost index speeds from the TLR or ACARS--per the GOM I might add--you maximize your block, and increase the odds of locking in a few minutes of OB here and there.

Why not follow company policy and fly Econ speeds? If you aren't trying to catch a commute, you shouldn't be flying any faster that CI/ECON!!!