if the signal you feed into the SSP is too low in level, you should amplify it / scale it before you feed it into the SSP, so the SSP has a signal of maximum amplitude to sample / digitize. Of course you should scale signals using a high quality scaling / amplification module. If you can do this outside your rack, I recommend a small mackie mixer. Proven quality, has been around before the existence of eurorack and cheaper than some eurorack modules that do amplification.
OK, if that is the case, maybe the behaviour there should be changed.