Sorry for the late reply. I did not see your edit to your VM till just now.
In the Arceus update, unhide the Update notes. Then Find:"Checks in Order of Overall Effectiveness" - you should spot it without any problem.
First, even if its listed as a check, sorry but i dont give a fuck about it, sometimes, analysis say the worst thing and nobody check it.
Now, as I said in my post but it seems you didnt read it, there is a difference between being able to check someone, and being a check TO someone. If he was a check, he would be able to switch in, since yes, a check need to be able to come ...
The difference between a check and a counter is slim indeed, the check cant come as he want, he need to be aware of something (like a move or taking too much damage if the game is too long), a counter dont give a fuck about anything, he can and put his ass on your face.