What they do is tell you that your current week is worth lets say 400,000 points and that if you purchase a studio for $8000 with a MF of $600 or so, you will have 490,000 to use in the system. Current MF on the Silverleaf week is about $900. You want the points you are ok with paying the $8000. Fast forward a few months later you get a bill for next year's MF and instead of the $1500 you were expecting, you get a bill for $3900 because now instead of calculating the original week as a week they changed it to calculating it by the point so now that MF more than tripled on the high season high point week vs keeping it in weeks. I don't have any first hand knowledge but this is the way it has been described to me.
So let's say when you converted your plantation resort to points and paid the conversion fee to do so and were happy with the 105,000 points but found out months later that instead of paying $800 MF for the week, the conversion now changes the way your mf is calculated and now you own $0.025 per point or $2625 for that week. Unless that was specifically spelled out in the paperwork it is really deceptive especially since other conversions don't change the way MF is determined.