the only problem i could see in having to run two races with the same tires is…. what if someone isn’t at say the first race, but then showed up for the second one…. they would have brand new tires and nobody else would because they ran the last race…. and especially in a high power class like shifters new tires mean a lot for the whole race day.
The spec tire rule saved us money this year. Saved on testing, motors, buying 3 or 4 different sets of tires to see which was faster.
One of the best ways of increasing the cost of racing is to have an open tire rule. Almost all major sanctioning bodies have a spec tire for this reason.