But in this case this guitar is for me and as I said at the beginning this is a "tweakers" guitar! I'm a freak about dialing up the tones in my head with amps, effects and routing options (to a degree that some people say I must have dog ears because sometimes they can’t hear the difference! Hehe) so doing it with the guitar itself is just the logical step for me!... With these phase switches I know that in many cases I will have to "flip back" to the upper in phase position before flipping another one or it'll become a mess!
Still nothing is written in stone yet. It is only a mad scientist experiment at this stage! Theoretically it sounds interesting to me to be able to phase shift the coils of a P-Rail (based on my experience I can imagine some exotic tonal colors that can result from this option that I think might be really interesting) but you're right that on any other pickup it would be completely ridiculous, but until I try it and judge if those tones are of any use, this feature is subject to change.