Continued judge of routine measurements by GR&R results

[zoosue]

A sample is measured periodically to control the measurement system. In our rule, the variation of periodic measurements (TV) can be compared to the variation of GR&R (GRR) to verify the need for periodic measurement items, as follos;

TV<GRR: Routine variation is evaluated by GR&R, so periodic measurements can be stopped.

TR<GRR<2TR: Much of the routine variation is evaluated by GR&R.

GRR>2TR: Routine variation should be continued due to high variability.

I have never understood why the 2TR is used as a boundary to determine the continuation of periodic measurements. Do you know if there is any basis for this?