Yes, that's what I did last year. I got a voucher last fall, but my AP didn't expire until early April. So for several months I had an active AP and a voucher, both with the same name and in the same account. I didn't have any issues activating the voucher in mid-April after my previous AP had expired, I just showed the barcode on my app at the ticket counter and they printed off a new AP, easy peasy. Since they don't have renewal discounts, it didn't make a difference. I was going to hold off as late as possible to activate, but friends ended up coming into town, so I only had a week between expiration and activation.
The main strategy with that is to lock in the current prices (though for me it's not going to end up helping as I decided to upgrade to Premier again after buying the voucher). Some people also were able to use that to lock-in the previous Premium AP benefits; they bought the voucher before the Premium stopped being sold, then waited a year to activate (vouchers are only good for 1 year), so they were able to continue on with their Premium AP with no blackout dates for almost 2 years after they got rid of them.