Keith is right! The short answer is for every one hundredth or thousandth of a second you cut off your short time it will carry through and come off the total elapsed time. Assuming no breakage. SO, Using Dave's numbers above the run had a 60' time of 1.2598 for a total E.T. of 8.7049. If he can better the 60 foot time to 1.20 flat the .0598 gained time should carry through to the finish line for a total E.T. of 8.6451. As Keith says if he can pick up more time between the 60' and eighth miles those gains become cumulative and reduce the total E.T. even more. If he can quicken his back half that is cumulative also. Hence, why Dave is comparing the 3.196 back half time for the run on the left to the 3.193 on the run on the right. The car actually slowed 3 thousands of a second in the back half on the faster run. Rumor has it Dave lifted!
Incrementals look like this:
View attachment 109142
As you can see the greatest gain (gain meaner quicker time) is in the short time. racers look at that because that's where they can have the most effect on the run.