If you are transfering PVTSim EOS volume shift values to the HYSYS, then be aware that HYSYS has an error in their implementation of volume shift where they require input of the "negative" of the actual value for "c" (volume shift with units) instead of the original-published and industry-implemented volume shift which is defined as:
v(adjusted) = v(EOS) - c.
However HYSYS implemented v(adjusted) = v(EOS) + c
(where v(EOS) is the molar volume from the original 2-constant (a,b) EOS of SRK or PR.
I hope this helps.