By the way, calculations show that Centaurs with Intelligence (I) = 10 cover the distance on the ATB scale [0; 1] slightly faster than Ents with I = 7 covering the distance [0.25; 1].
More precisely, the difference is about 0.07 ATB seconds.

I don't know for sure if this is significant, but it seems that hundredths of a second are used in the calculations... I've never checked it myself, because I don't think it's important to compete with Ents in this. :)