I’m evaluating some equipment and ran a few null tests of my analog mastering chain. I wasn’t too surprised that there was not a complete null in WL, however, when I did the same test procedure in Pro Tools, it nulled nearly completely. By comparison, the WL null had plenty of audible musical content in it, and it was also slowly drifting in it’s “presence”, which would indicating a drifting synch or clock kind of thing I’m thinking…
Certain deviations to a decimal scale reflect different results in the digital realm.
There will always be differences even if in the order of -120dBFS (for other reasons) , you must choose the program you feel confident to work with and gives you the best final results.
PT does not use VST-3, nor it renders in 64-bit float, AFAIK.
Maybe some plugins behave differently according to their format. Normally, they should not, of course. But if you really want to know, you must check each plugin one by one.
But something sure, WaveLab does not add processing to the signal “from nowhere”.