Nay, I didn’t “get you”. If you are hanging out in this forum a lot eventually you will see somebody starting their message with “I asked ChatGPT…” or “I googled this…” and those machines will then have presented some random text from this forum.
ASIO Guard has a fixed size. To us it is shown in milliseconds but it is actually an amount of samples. Furthermore it works in packages, ie. the amount of samples is wrapped into one package and then delivered to a certain place in the Cubase audio engine. Any further audio signals will be put into the next package. It is a boxing service if you like.
My GUESS is: The meter shows how many of the available samples per package are actually filled up with data, ie. how full the box is (and how much empty space is left inside).
I might be totally wrong on this one, though.