I think you and Chef are describing the same thing. With mine it's clear both coils are on but one is darker. It's a great way to get a split coil sort of range from a single pickup; why it was removed in favour of a plain series I don't know. Not that I'm dissing the latter; it just seems a bit obvious whereas OMG is a special sort of magic which - although it needs applying carefully - gives a whole new voice to the pickup.
Previously to the L2K I've never been happy with the front pickup sound on any two pickup basses. They always few like the miss something of the way a P bass blooms and clatters the notes out at full chat, instead falling on the side of a wider frequency range.
Personally, I love the single coil setting on the neck pickup of an L-series. On the L-1000 it's the coil nearest the bridge on the neck pickup and it's almost exactly where the single coil would be on an older P-bass. But it's an MFD single coil and is so, so nice. The k-mod I did on my L-2500 is for the inner coils so I could again have that bridge-side single coil in the neck pickup.
I do get what you love about the OMG setting which, oddly sounds really great as you crank the bass back. I think it's that you're getting a blend of the two coils in series: one filtered, one not filtered, together in series. And the bass cut control doesn't cut all of the frequencies emphasized in OMG mode so you get a really interesting frequency spectrum from the bass.
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