Step/Dir Spindle runs SLOW

I'm trying to set up hybrid motor for my spindle on a small lathe. I think I have the wiring correct. M3 and M4 turn the motor forward and reverse.

At present, the motor is not actually driving the spindle so I have de-activated the index.

But I can't get any real speed out of it. The motor has a default value of 4000 steps per revolution. I changed that to 1600 s/r.

With a value of S400 I only get 31.5 rpm. With S3000 I get 46.0 rpm. Hardly linear.

If I lie to Mach3 and set the s/r to 16,000, the rpm's increase to a predictable 315 rpm and 462 rpm.

I have to think it's something in my setup but I'm out of ideas and hoping someone here has something for me.

Update:

Last night I disconnected the new hybrid motor, dug out an old G201 and an even older Pacific Scientific stepper and hooked that up. Same slow result.

This morning I changed those outputs from spindle to 'Y' axis. (Should have thought of that in the first place). The motor acted normally.

So, the issue is defiantly with the step/dir spindle function in Mach3.

Has anyone gotten a step/direction spindle to work? What version of Mach3 were you using? I'm using 3.042.029.