That thought is in the right direction Apex.
Calculating the average from 40 Master scores in saturation, a single shot counts 1/40 = 0.025. That means that instead of 60.003, only 59.995 and 60.000 are possible as well as 60.005. The two former would be good enough to tier up, the latter would display as 60.01. None of these options is the case here.
His score history is shortened to less than 30 Master scores, but these are extraordinary, all around 30! Perhaps he played no ranked round from Sept '14 or longer?
Please allow me to guess that the average is not yet saturated, some scores missing towards the progression to TM tier. In this case, intermediate averages like 60.003... are possible due to the various denominators below 40.
Edit: It's not the total ranked rounds but only those in the respective tier (excluding Par3s and Par5s).