Hey, I'm coming over personally. My apologies for the delay.
Thank you JohnBob for posting my remarks and lynx for checking and taking them.
Before I start, this information is from decompiling and testing on version 2.5.
I am far from being an expert, but unless I make a personal error or change in version 2.6, the information is quite reliable.
I should point out that my English is so-so.
I did some « not good » testing at the time but what I know is that these choices are not implemented in the game engine.
For some opcodes it works fine : 55, 109, 175, 177, 185, 238, 283, 319...
But not for the following ones: 100, 178, 179 & 219
Maybe it is a bug but it is easy to test. Effects with Type 6 are cumulative, like 0.
This mode is used internally by opcode 12, for flags 7 & 8. And, yes, these effects are not cumulative.
BUT this restriction is configured in opcode 12, not in opcode 18.
So, this mode does not stack if used by opcode 12 because opcode 12 checks if a mode 6 effect is active but if used directly from opcode 18, there is no restriction.
Fake or patched.
Thanks to you