I was so excited when this feature was introduced.
Unfortunately, it never worked for me.

I'm using callout commenting tool mostly on P&ID drawings (engineering documents).
Most of the time, the paper size is A1 or A0.
When using the feature, the callout size changes but in a way that looks like arbitrary.
Using more than once the feature increases the callout size each time.
Default callout added:

Automatically resized with fit text:

Thanks for your help.