B-26 WEP key still works. Or, thinks it does.
There's no boost in MAP, RPM, or fuel consumption, but when WEP is toggled, the MAP sticks to the end. If you try throttling back it has this 4" to 5" buffer zone before it drops (so it goes from 55" to 50/51") then once the WEP is "off" you can set it wherever you want once again. In planes with WEP you see the same thing, you can throttle down to turn WEP off, but you need to throttle back past a certain threshold for it to kick off. I hope I'm describing that clearly enough.
Must be left-over code from when the B-26 had WEP.