actually it seems like the E.T is slightly high for the mph/whp.
The trap speed on that calculator is dead nuts to what my car trapped vs my whp/weight but the E.T is about .4 high but most of that is in the 60'.
Calculators aren't usually accurate on ET because of the variables but trap speed is easier to calculate given weight and hp
It's within 1 mph of my trap speed and whp dyno also... hmmmm.