Thanks to everyone who weighed in, I finally got a Canadian-based rep on the phone and he understood what I was trying to immediately.

Net net: I was not "breaking the rules". Because of the lack of P space on the FLL-YUL he did have to book be up to "D", with an upfare as expected. It's quite the racket where I have paid them for the opportunity to now sell the YUL-YYZ to someone else However, I can now check a bag if needed, and don't have to worry about being flagged in some way by no-showing for the YUL-YYZ ("Mr. Simon, that's a hidden city fare..." the week I hit 2MM status!