Whenever you buy a new contract, it will be added to the same membership number as long as the named members are the same and the use years are the same. The contracts are in fact listed separately in your online account, i.e., it will show the BWV and SSR contracts separately in the account, and thus distinguishing the use between them is easy.
As long as the same member is named on the contracts, even purchasing a new contract with a different use year, and thus different member number, results in that new contract being placed in the same online account as the first one, but with the different membership number, and you will not be able to use the points from both contracts together to make a single reservation unless you transfer points from one to the other.
As to keeping track of the booking window, that has nothing to do with how contracts are listed in the account. You can always book 11-months out from date of intended arrival using points applicable to the particular resort you want to reserve, and 7-months out at others, e.g., your BWV points can reserve BWV at 11-months out, the SSR points can reserve SSR at 11-months out, but they cannot be used together to make a single reservation except at 7-months out.
As to knowing how many points you have in any partricular use year still left for each resort, in your online account, under "MY
DVC" go to "MY Vacation Points" and you will find the answer.