seeking answer for GR&R questions

great confusion encountered during supplier audit about GR&R recently, anybody can clarify them for me here? thanks in advance.

1.in what situation supplier should conduct GR&R study? the answer i got from supplier is when costomer required, that is not a correct reply, i know one situation is that they introducing a new gauge, they should complete Bias, Stability & Linearity analysis then GR&R, any other situation??????

2.what is the diference between GR&R and PT value, should the two criteria both be evaluated in a GR&R report? or one can represent another??????

3.all GR&R reports supplier submitted me are just including a result of GR&R% value and ndc value, is that enough??? should supplier conduct further analysis such as Xbar-R/S chart for the result?????

4.any good heart man can share me some excel templetes for Bias, Stability, Linearity analysis, as well as Xbar-R chart??????