mixdown loudness levels different on export vs import (both stereo)

I’m hoping there’s something simple I’m missing or doing incorrectly here. Thanks in advance for any ideas!

On my projects in Cubase 9.5 Pro, I insert Ozone 8 Advanced on the Stereo Out track. I leave the Stereo Out fader set to 0db and use Ozone’s maximizer to keep true peaks going no higher than -1. I confirm this with Cubase’s loudness meter, and then export the mixdown from Cubase as a single stereo .wav file at 24 bits and 48khz.

For some projects, I need to import the mixdown .wav file into an empty Cubase project file for additional processing. Upon doing this recently, I discovered that the peak loudness levels on imported files don’t match what they were when I exported them. Or at least the Cubase meter levels aren’t matching up.

On a recent instance, Cubase’s loudness meter showed a true peak of 1.5 on an imported .wav file, even though the true peak reading never exceeded -1 at the time I exported the same file.

Initially, I thought that the difference might somehow be caused by having Ozone (especially the maximizer) inserted as a pre-fader effect, even though I have the Stereo Out fader set at 0 on both project files. So I shifted Ozone to post-fader before exporting. But that hasn’t made a difference.

Why would Cubase’s loudness meter show one peak loudness level for my mix at the time I export a mixdown, and then another loudness level when I import that same mixdown file into another empty Cubase project? How do I know which reading is correct?

I saw another recent thread where differences in mixdown levels resulted from stereo signals being summed to mono, but I’m working with stereo at both export and re-import.

Many thanks!

Okay, after a bit more tinkering, I think I’ve figured it out. I hadn’t realized that putting an imported .wav file into musical mode and shifting its tempo even slightly alters the peak loudness levels. That appears to be what was going on. So in the future, I’ll apply any loudness control measures only after such changes.