Okay - you lost me here:
"Free cruise works out because the cruise lines are at 60% occupancy usually."
That is completely wrong - the average reported occupancy on all major cruise lines is over 100% "berth capacity" - which means all of the regular beds in double occupancy cabins. They go over 100% when they include third and fourth passengers in cabins in temporary beds.
Say what you want - if you are willing to put up with the boring presentation, AND all of the red tape you go through to actually get booked on the "free cruise" then I guess you have far more time on your hands than I have.
I have gone on "free" timeshare vacations before. I always felt like a freeloader and never enjoyed the property. But if that works for you - okie-dokie.