Allowing only Annual subscriptions

Currently we have annual and monthly subscriptions both get access to the the whole site. So they are in the same group. And if someone changes from monthly to annual the annual subscriptions starts when the monthly ends (so there is no overlap). I am trying to do a promotion that everyone with an annual membership gets 1 more page, so people will convert from monthly to annual. Its very easy to give users with an annual membership access to this page... but not if they have a "FUTURE" annual subscription that hasn't started yet... that is where I am running into big issues.

The only idea I have is below:

My question is if we set it up so everyone with product X gets access to a specific page.

Then give everyone with an annual membership product X with the "Mass subscribe members" feature.
Also, give everyone product X for free that purchases an annual membership (ability to do this in amember admin).

What happens to users that currently have a Monthly membership but purchase an annual. Their Annual doesn't start for say 2 weeks (when their monthly ends because its in the same group). Will they still get product X NOW... or will product X not start till their annual membership starts in 2 weeks?

Will this work?
If anyone has any other suggestions I am very open!

Thanks

Edit: Oh if it helps i am using the wordpress plugin for content/page protection.

I'd have to test this, but what about using the "Additional subscriptions" function in 3.2.3. Youd make an additional product with access to the content. I'm not sure if it will add the additional product if the current is set to future though.

David