I had a quick check of the levels from Arturia plugs ins, and this is what I got, using a dry pure square wave on middle C
dB output
Matrix 12 -16.3 (default level) -9.8max
SEM -6.2 @0dB +14.2 max
Solina -9.8 @0dB +14.2 max
Vox -12 @0db (0dB is max)
Wurlitzer -13.5dB@0dB -3.5 max
2600 -1.2@0db +18.7 @ max
CS80 -9.6@0db -1.9 @ max
JP8 -2.9 (max)
Mini -7.4 @0dB -1.4 max
Modular -8.1@0dB +27.8 max
Prophet +1.7 (at 1) +11.2 max
Probably shows the inconsistencies that everyone is noticing, the Modular V can be a bit violent with it's level - and it seems the Vox is the quietest, followed by the Matrix.
The biggest inconsistency is what Arturia seem to classify as 0dB, although they may be a allowing for what the effects can do to the level, which I didn't test