Never having used the 'V' I do recall that some versions have a dual 6/12 switch: a Parallel programmable bit (PPB) that decides how the processor start up (and continue if no change) and SFR bit that can change between 6 and 12, but only if the PPB is set to 12. The confusion may be due to not realizing what bit is discussed.

Again I do NOT know if the 'V' is like this, but some others are.

Erik