Okay, I did look into this (quite briefly) and saw some abberations.
First, "PACK" may begin on 16n + 8 offsets sometimes.
Second, files only begin on 16n + 8 offsets sometimes.
I did modify the tool to switch between classic (16) and abberate (8) version. Try 1.1 version of PsyhedelicaPCKTool.
So you could extract any (I hope) archive from 16 or 8 version (try 16 first, if it's not working, then switch to 8).
And pack to either 16 or 8 (pick the one with which game doesn't crash).
Unpack version and pack version doesn't need to be the same.
(Theoretically there could be a case then PACK starts on 16n + 8, and files starts on 16n, but I won't implement it unless necessary).
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It has a CLI interface. First version (8 or 16), next enter mode (0 for unpack and 1 for pack), next enter the pck archive name (with extension!), next enter the directory name.
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Still I did test quite brief, so I could miss something.
Write if some game crashes after repacking (after trying to repack to both versions) or there is still some problems in extracting.