Some industrial laundries do this, but I have heard this over and over again to describe residential HE laundry machines but never actually seen one with a way to measure this. The usual method is to tumble the clothes until the water level in the tub stops dropping. Now they're saturated with water.

What you are probably getting when you start your washer is an estimate considering the steps of the cycle and loaded to capacity. Some machines have turbidity sensors - mine doesn't - this could deliver information that might shorten the cycle. Also the time may go up if it has to deal with suds or stops spinning to rearrange the load if it shakes.