I tried to explain that, but I guess I wasn't clear.

In general, front runners "use" themselves during the first 1/3 of a race (sometimes longer). If they are able to run a little slower than average early and relax (getting loose is even better) they will run a somewhat faster final time than usual. By "USE" I mean the fractions and the competiveness of the situation (dueling, loose etc..) For most horses I am talking a couple of 1/5s, but for some it can be more.

If they run much faster than usual and are used harder in a duel then they run a slower final time. Duels like that are fairly clear in their impact when they are extreme.

Closers and mid pack horses experience the same phenomenon - EXCEPT - it occurs during the middle portion of the race when they are trying to get into contention on the late backstretch into the turn.

If the first 1/3 or more of the race is unusually fast and competitive, then the middle is often slow and lacks competitiveness because the front runners are all dead or weakened. The closers make their move into contention running on their own courage (without being used hard) and meet very little resistence as they are trying to pass horses that battled early. That more relaxed and less competitive situation allows a closer to finish in a faster final time - just like a front runner that gets loose and runs relaxed on the lead gains a similar advantage.

It's not purely a matter of how fast or slow the pace was. It's a matter of how much energy the horse used to get and/or maintain position in order be in a position to win into the stretch. Being used hard can occur at any time, but there are typical race developments as described above.

TMW, sat off the contested pace. When he was ready to make his move there were no other fresh high caliber closers he had to loop to get position, no pace strong pressers that were making their runs etc... He had two horses in front of him. One was totally exhausted and the other was very tired. So he blew by them. He was never stressed at any point in the race and that allowed him to run a little faster than usual (as well as win of course).