It appears that I have been misusing the term SKC, which is actually the seven-digit number which must be used in conjunction with a workshop code and the importer number of the dealer that generated the code.

The four digit number, which can be extracted from the 95040 or cluster and used to login via VCDS, is more commonly referred to as the "PIN" or "login code" (once you add a zero to the front, making it a five digit number).


^This.  
However, in the three examples that I have to verify the info, all three are placed differently in the HEX, and I currently don’t have enough cluster dumps to really verify the info beyond the screen-shots below.







...or the attached VAG locksmith PDF
courtesy of EuroXs4

There is a LOT of info about cluster-hex-tweaking on the TDI forum, specifically these:
“IMMO3 cluster in IMMO2 car”
"Immo3 Cluster Coding... Getting the SKC/PIN"
"Cluster Dumps"

knowing where are locations of Immo and keys in rb4 dump won't help you too much because you can't just edit them in dump - the Immo part is crypted ( ok its possible in clusters from MY2001 and begining of MY2002 because they aren't crypted )