If you called on Jan 1st to reserve an 11+7 reservation for Dec 1st-8th, but you actually wanted Dec 9th-16th this system allows you to call back on Jan 2 cancel the 1st add the 9th, until you get to the 16th. With my proposed solution, you could not cancel, but only add days. You would in essence be stuck with a full two week reservation before you could free up any points. So you could not "walk", you could merely reserve more days than you want.
Admittedly, maybe I'm confused on your proposal, but....
If you could not cancel,but only add days, until the 11 month window exactly, you'd only need 2 extra days of points, right? Not an extra week?
You reserve the 1st - 8th. You want the 9th through the 16th.
You call on January 1st to make the first reservation.
You call on January 3rd to add the 9th and 10th.
Now, your room will not be "free" to anyone booking until the 11th, right?
TECHNICALLY your exact 11 month window, to cancel the rest, would be the 9th, right? Because you'd now be exactly 11 months from that date. You would be able to cancel all days prior to that. So, on the 9th, since you already have the 9th and 10th (and nobody can touch them, now, until the 11th), you call back, cancel the 1st through the 8th...and add whatever days you want to add.
Or are you proposing that EACH time you add a day, they extend the 11 month window to THAT day? So if you call to add days, your "cancel window" gets extended? I'm not sure, systematically, that would work either since, I suspect, they handle "extensions" like they did DBD booking.....