It never hurts to call and ask Member Services. I seem to remember the rules saying you have to use all your current use year points before buying one time use points, but it never hurts to call and explain the situation and see what they say.
I had the greatest MS CM yesterday, I don't remember her name, and I wasn't doing any creative point use things...just adding a friend to my reservation for next month. She was so efficient...she went through and added him to all my dining reservations, added him to the fireworks dessert party, took his credit card info for the dessert party payment, added him to DME and added him to the River of Light dinner, as well. Explained to me how to add him to fastpasses on the app. She was so pleasant and so nice. Everything a Disney CM should be!