Something about quad_x tailsitter vtol

This type of plane do confuse me.
As show in the picture below, it has four motor, 1, 2, 3, 4, but the text on the right show 1, 2, 4, 5, why?
And * MAIN7 : canard surface * MAIN8 : rudder, but the mix file do not contain the mix,
Anybody help me out?

the mix file above is capture from v1.9.0

the mix file below is capture from v1.8.2, there is a ZERO before elevon, so the elevon should connect to PWM_OUT 6 and PWM_OUT 7
But the picture above show 5,6.
this really confuse me.