This tire test was possibly one of the best-ever documented tests made (same size, same advertised tread wear rating at 200, same tire psi f/r).

I think some factors, however, as the day progressed, could have some critical influence (in respect to time results in the 0.001 seconds):

(1) day's temperature changing (cooler morning/warmer mid-day/cooler afternoon),
(2) amount of fuel in the tank (progressively less weight changing the balance of the car),
(3) did the tires acheive their intended best rubber temperatures... although, 5 equal runs should be square enough amongst each other,
(4) order of which tires were run when in the day.

Again, a great documented test that can influence selections for us. But also, at some autocross sanctioned championship events (SCCA, others), some tire brands do offer contingency awards for running their tires if you place 1-2-3... so, that is a high factor in seeing who runs what and when/where.