I 'm not sure how table ttadv312 is filled and what it contains ?
For example, I have a form definition in the VRC B50 b.
And in that session I have several records where source VRC is always B50 b and object VRC are all different !!!
There is no definition form in those VRCs, so I don't think it's correct.
What do you think ?

GCharles,

That's OK as ttadv312 contains a list of Dumps by Form and it is possible to compile/dump a form from an older PVRC into a newer PVRC if that form uses labels from the newer PVRC. Hence you would only have 1 source VRC but several object VRC's.