EMC steps/rev calibration

I'm getting about half of the motor revs per inch of travel that I
want, and can't figure out why.

My setup: EMC with 5 tpi screw, 1024 cpr encoder, and G340's in x5
mode.

I have INPUT_SCALE = 1024 0 and OUTPUT_SCALE = 1 0.

When I jog 1 inch (any axis) I get about 2.5 motor shaft rotations. I
expect 5.

Any ideas? TIA

r