It sounds like what you are trying to do is reserve the first five nights at 11 months out and then make the switch of points at 7 months out from your arrival date so you can then add the last two nights at the same time using AKV points, and thus do not have to wait until 7 months out from the last two nights to reserve those using SSR points.
I had a similar situation a number of years ago and it was actually a little tricky as to what one could do. If at 7 months out from your original start date, all five of those nights already reserved are separately available, they will allow the switch, and, obviously, if the last two nights you want are also available you can just redo the reservation to give you the entire 7 nights.
If any one night of those first five nights is not independently available, they will not allow a switch of any points. Example: if the fourth night is not independently open, you will not be able to switch the first two nights to SSR points in the reservation you have. As explained to me that was because the reservation you have does not distinguish between particular points applicable to each separate night. However, in that situation what you can do is drop the first two nights of your exisitng reservation and then make a separate reservation for those first two nights with the SSR points, and add the last two nights to your original reservation number using AKV points and link the two reservations. Nevertheless, if either of those first two nights is not separately available, the change will not be allowed.
One question to answer is whether it matters. If you are going to be making a reservation at 11 months out any time fairly soon, then for the time of year you want you will likely easily be able to get AKV standard or savanna view at 7 months out. If what you want is value or club level, then the switch will not likely be allowed because nights you have already reserved will not be independently available, but it probably won't make any difference because those last two nights you want to add to the intial 5 night reservation are themselves likely going to be gone when you try to make the change.