Hey Michi,
You are contributing with your tests already - don't worry about not paying!
Now about this issue: I know. I just didn't want to stall the release yet again to fix this issue first (I originally intended to release version 6.20 in March of this year
without declipper and improved clipper etc, but still). I will fix it eventually...
BTW: In the (I should make a shortcut for this so I don't have to type it this often
) huge redesign that I've planned, one of the changes is that the VST and STS (or maybe even a new format) interfaces will not be separate code paths anymore, so differences like this won't occur anymore.