Here is an interesting TFL post [1] on making and using Tangzhong with a bit of history included. It is interesting to note that originally the cooking temperature of the Tangzhong was specifically 65C - the magic mashing temperature for beer production and of course no coincidence.

Indeed the original title of the Bread Doctor book was "65C Bread Doctor [2]"

I think the 65C rule is now widely disregarded and possibly not known to many, so I guess it still works even if you go higher, perhaps without producing as much sweetness.

Lance