This whole thing about the "Bashed Patch" is another one of the big mysteries to me. Borrowing from Return to the Future these are the Universe, Women and now the Bashed Patch... But I have to get to that later on, so please for now nobody bother to explain me anything on that. I want to read some more and try some self-education first.
The base reason for the bashed patch is this:
Assume Mod A changes a specific NPC's eyes, Mod B add's a weapon to its inventory and Mod C changes its level. Since all three mods change the same record (the NPC), the one loading last (Mod C) will win and overwrite the changes from Mod A and Mod B. So the NPC gets vanilla eyes and weapons, but changed level. When building the bashed patch, you effectively create a new mod (the bashed patch is an esp file just like any other) that contains three changes for that NPC, the eye from A, weapon from B and level from C. Since the bashed patch loads after the three other mods, it wins over all three and makes all the three changes apply to your game.
It also has more advanced features like merging leveled lists: if Mod A adds the possibility of finding a dagger in a chest, and Mod B adds the possibility of finding a scroll, the bashed patch will add the possibility of finding both. This is cruicial for FCOM, because OOO, MMM, Frans and WarCry all tend to add their weapons or creatures to leveled lists (a leveled list is a list of what you can find a certain place). Without the bashed patch, the last-loading of the 4 would wipe out the other 3, but the bashed patch reads the additions to each leveled list from all 4 (or other mods that do the same), and combines it to one bigger leveled list stored in the bashed patch.
There's of course more to it than that, but this is the main reason for using a bashed patch.
Ahh, and NiceOne: Is there a dedicated thread for your MMM OMOD installer? I want to install MMM soon as my next step towards FCOM, now that OOO 1.34 is under my belt. I'm sure I'll be having questions then...
It's http://www.gamesas.com/bgsforums/index.php?showtopic=995334