I saw several discussions recently regarding PKS. I thought PKS is an obsolete product? For synthesis, it is RC. For P&R, calling PKS is optional (and I don't see a reason to call PKS). I think there is no R&D on PKS anymore.
Anyway, physical engine in Encounter is not PKS, although you can call pks for netlist-to-netlist optimisation. PKS is not use for SI; it is Celtic.