I'm not using the archive capabilities of the OSX Finder; I'm not doing drag-n-drop to add mods to Minecraft.
I'm at the command line, un-jar'g, un-zip'g, and jar'g myself. I use rsync (w/o --delete & w/o --update) so that directories are merged and not overwritten, timestamps are ignored. My tools are fine. They've worked for ... ages.
In vanilla MC, there are two codecs: CodecJOrbis (8,100 bytes) and CodecWav (5,338 bytes)
In Forge 608, there are three codecs: CodecIBXM (7,898 bytes), CodecJOrbis (8,229 bytes), and CodecWav (5,459 bytes)
Once my tools are done merging MC and Forge, I have three codecs: CodecIBXM (7,898 bytes), CodecJOrbis (8,229 bytes), and CodecWav (5,459 bytes)
Seems right to me. So how am I supposed to know if "paulscode" was installed (in)correctly?
I've watched several videos on how to avoid the "paulscode" issue. They're all basically the same. I've done it. I do it. It doesn't help. The issue is not with "bad archivers." The issue is the assumption that everyone uses a Windows-like GUI to moves files via drag-n-drop. Windows is the only OS that "merges" directories when you drag-n-drop a directory onto one with the same name. (Not true: OSX 1.7/1.8 now has a "merge" option in this situation.) But that's not the point ... I don't nor ever have used the OS file GUI to tweak Minecraft. If there are newer/different codecs (for example) in Forge, then they SHOULD overwrite what's in vanilla MC. What SHOULDN'T happen is a Forge directory shouldn't REPLACE an existing MC directory, it should MERGE with it. Again, that's not an "archiver" issue, that's a file GUI drag/drop issue. Since I don't use the OS's file GUI and I've worked hard to make sure that directories are merged, the "bad archiver" issue is not my issue.
And I don't understand your statement: "We replace a class in that folder so it got overwritten when you installed forge."
"It" = "a class" -- isn't that exactly what's supposed to happen?