Just as a side note, i don't think the instruments were calibrated for the extra amount of power, at least not early on in the war.
Boost cut-out probably started as an over-ride in case the automatic boost control failed, then pilots discovered it could be used to over-boost the engine. As such, it went from a backup system that was supposed to be used to maintain boost in normal operating range in case of malfunction, to a war emergency type system and instrumentation had some catching up to do. Viper2000 explains it in much more detail, possibly in the threads you guys linked.
As for the 100 octane issue and boost values, i agree it should be corrected but if the CEM is also realistic it will be of minimal tactical value. I mean, what is a minute or less (depending on the engine's temperature at the start of WEP usage) of running +12 psi boost before it gets damaged in the grand scheme of things during a sortie? If people think we'll be able to cruise around at those values they will be sorely disappointed.
Such power settings are more like what you would use when you see a 109's cannons "blinking" in your direction to command extra power for a maximum G evasive maneuver or to accelerate better, ie as a backup for when you've already put yourself in a place that you've probably lost the fight. It certainly doesn't represent any kind of sustainable power setting if it blows the engine to bits within minutes, it's just an "oh sh*t, let's get out of here" helper