&proi_version will include the version( often the same as revision) and iteration number (G.2, F.3) or whatever your scheme is, where the iteration is bascially how many times the object has been checked in.
&proi_revision will only include the version (G, F).
For us, adding the "wm" designator makes no difference. For example, &proi_revision and &proi_wm_revision are the very same parameter.