Most positive displacement blowers will hold 16"-19" before bogging the motor or slipping a belt, some with enough horsepower to spare will develop 22"hg before bad thigns happen, it really depends on the unit.
My point is your TM doesn't "have" lift, you "set" the lift, and the lift is dynamic, it's constantly changing in relation to the airflow, the tool, the carpet.
It would be a better question to ask what is the lift you are currently set at, and what does the blower vacuum performance chart say the CFM is at that lift. ie: 14"hg and 298 cfm.
If this somehow relates to portable vs: truckmount CFM/Lift:
I have a poll going on the Recoil board, check it out and pick a number, there is a cash reward for the winner. I go to the recoil board by hitting
www.OCIBR.com and go the Cleaner's Hub link on the left, then click the recoil button.