You can add on points at any
DVC resort. Minimum add-on is 25 points if paying cash, 50 points if you want Disney financing. The points will be the same Use Year as your current BWV contract. If for some reason you wanted a different UY, then you must purchase a new master contract of a minimum of 150 points.
If you purchase an add-on at a different resort, you will have the home resort booking priority only up to the number of points you own at each resort. This is better explained by example: You own 150 BWV points and add on 50 VWL points. At 11 months from your check-out date, you can use your 150 BWV points to book at BWV and your 50 VWL points to book at VWL but you cannot combine the points and use all 200 at either BWV or VWL at 11 months out. If you wanted to use the VWL points to book at BWV (or vice versa), you would have to wait until 7 months out to do so.
Prices to add on vary by resort:
$95/pt at BWV, BCV and VWL;
$92/pt at OKW;
$87/pt at VB, HHI if the discount is still in effect otherwise $92/pt;
$91/pt at SSR if the $10/pt discount is available for smaller add-ons, and $86/pt if you purchase at least 115 points (this deal may be expiring soon).