in the case of the oscillators and pitch inputs on the SSP, when you set the coarse/fine to 440Hz, this will be added to the frequency which is derived from the pitch CV signal fed into the pitch input of the oscillator.
for other parameters / modulation inputs of the modules in the SSP, the modulation signals are applied around the parameter value as you describe. So the bipolar modulation signal is first mapped to some range of values and then the result is added to the parameter value.
the SSP’s I/O has been designed for -5V … +5V signals, and has to be plug and play compatible with a CV keyboard that you plug into it, giving you an almost 10 octave range.
I don’t know if this would solve your problem but you can offset signals in the patching grid of the SSP by using the DC module. Send the output of that to the same input as you send your pitch CV signal to, and then change the DC module’s parameter to achieve to the offset you want.
Alternatively, maybe the bias/gain per-input of the input module can do the job? You can apply an offset there to the incoming signal.
I will add offset/inversion functionality directly in the patcher grid itself just like I did it for the scaling of signals, this has been discussed elsewhere as well.
If I’m still missing something here let me know…