Using Motor Test, Motors spinning at Different Rates

Hello. I am assembling and testing a drone with my team for a school project. Very recently, one of our motors stopped spinning. To verify whether it was a potentially faulty motor or potentially faulty ESC, we switched the possible faulty motor with a working motor. Using the motor test function on Mission Planner, we tested all motors at 10% throttle and each one was spinning again, however not at the same rate. The two which are spinning clock-wise are spinning at the same rate (one of these motors was the potentially faulty motor that we switched). Of the two motors that are spinning CCW, one is spinning faster than the CW ones, while the other (that which we had just installed the working motor into) was spinning far slower than the CW ones. I am testing them all at 10% throttle, so I’m not sure why the two CCW motors are not spinning at the same rate. Can someone help me, please?

You could try doing the ESC calcibration to ensure they are all responding the same