Well lets examine cylinder head temps.
What difference in cyl heads temps will you find between all aircooled aircraft engines?
If you own the airplane you are free to ignore shock cooling with large power changes, actually the proper description is thermal shock and it works both ways, ie. adding power and reducing power.
But hey, have at it and ignore physics, but I would not allow anyone to operate any engine of mine without consideration for thermal shock among other things.
Anyone who thinks there is a quicker thermal change after a normal shut down than when reducing power to say idle at flying speed may well be advised to do a little research on the topic, thermal shock is not a myth it is a fact of physics.
Then that is only my opinion and everyone is welcome to their own way of doing things.
Chuck