Motor Spin Differences?

While going through the calibrations for my quad, I found myself on the Servo Output page in Mission Planner. Curious to see how well the motors run while monitoring the gauges, I armed the aircraft and throttled up the motors (without propellers, of course!), and I observed the following:

I noticed that motors 1 and #4 values were lower than #2, #3. I expected all to be running close together. IS this something I should be worried about?

Completely irrelevant.
Have you not received this same reply before?
What Calibrations would those be that put you at this place?

The usual - accel, radio, compass. I am unable to do the ESC calibration via Mission Planner as my ESCs are T-Motor Air 40A and are noto digital. The only way I Can calibrate the ESCs is to connect each one individually to the receiver.

That doesn’t matter and digital ESC’s are not calibrated. Use the Semi-automatic method described in the documentation. It’s used for standard PWM ESC’s like you have.