Exactly 71.928 vs "sort of" 71.928

[sparktank]

So I've used this and I've used NVidia custom to get 71.928 for 23.946 (24/1.001) movies.

I have old Dell 1907FP that can do 60Hz or 75Hz on 1280x1024(maximum resolution).
Connected NVidia GeForce GTX 750ti (latest driver as of this post: 350.12) via HDMI-to-DVI(-Digital) cable.
I was able to create custom and run at 72.928Hz with no problem.

However, when I used madVR as the renderer in MPC-HC, it shows variable fluctuations between:
display 71.924xx Hz - 71.925xx Hz

I also have ReClock (v1885) installed and operating when I watch movies and RC shows a constant of:

Refresh Rate: 71.925 Hz (DDR)
Display: 1280x1024@72 (1/1)

Is this normal? I've read that values shift constantly as I've observed.
I mean for it be low as 71.924 as amdVR shows and 71.925 for ReClock.

I don't know what all the different settings mean. There's no real information I can find to see what effects what. Like I wouldn't know how to guess what different porch settings would effect how I get to 71.928 on my monitor.

Most "solutions" I see for getting 71.928 are for 1920x1080 monitors.

With Nvidia control panel, I see less settings than CRU (one less setting).
And if I use CRU, then I have to do some roundabout process chain to get it working. I can't remember but it wasn't fun. Something about interference from GeForce Experience (which I have uninstalled since).

ReClock adjusts videos from 23.976 to 24, so is this even a real problem if I get 71.925 instead of 71.928?

Any insight?