JTD, I think the problem lies in the definition of formal.
For you and I, formal = tux and for ladies = long dress?;
Now you and I have disagreed on this in the past but per Trip, I dress Formal but I suspect using your 'perceived by me' definition of formal, I dress smart casual.
I think the use of Formal needs to be clarified.
Now based on what you and other CMs have posted, I and others will never sail Cunard or P&O simply because of their dress codes. My choice but, for me, tuxes etc are just OTT. I suspect I would conform to all other vessels dress codes.
I suspect there is a geographical/age bias in this?