Besides the ability to hook consistantly, when the sfifts occur can have a big effect. For a class not allowing an air shifter on an rpm switch or similar setup, your ETs can vary a lot in a faster car. I noticed my ETs tighten by 0.01 to 0.02, because the 1/2 shift was just after the wheelstand. So the further out those shifts are, the more accurate the driver can be.