No other games than strokeplay and matches count in, matches only if played before Legend and won against a higher tier.
Furtheron, only the scores of the current tier count in.
This guy is supposedly special - he will not have played a single strokeplay round as a Legend(?). Thus, his average is still the value of his last promotion.
I have seen one or two of this kind, who - at some point of their career - stop playing strokeplay. They achieve their rises only by those matches against higher tiers. Starting as a TP or Master, they gain by not posting scores. Thus, the matches drop the score from the last threshold. 67 => 63 => 61. The minimum no. of rounds is somehow eliminated.
The downside of this may be a lack of XPs - low level, impossible to succeed from the tips. A restart candidate.