I don’t question your allegiance; was asking to which union you belong. You’re correct in not having to explain yourself to anyone.
I’m well aware that MM&P has no permanent 3rd Mates. Neither did MEBA when I was a member there, prior to joining MM&P.
I wasn’t aware of a two-tier wage scale for tanker 3rd Mates. Haven’t sailed in a tanker since the Eighties.