To be clear, there is no 4.0 plan. Let’s make sure we don’t create additional confusion with a name for something that doesn’t exist.
You have 2 phones, each with My Choice Talk, Text and 1GB of data.
If you pay annually, today or any day before your May 25 billing cycle, your 12 months of prepaid service will start on May 25. It makes no difference whether you pay today or May 24, it will begin on May 25.
If you want until May 25, after your next month has been charged, then your 12 months of prepaid service would start on June 25.
One of the phone users wants 2 GB of data. Do you feel confident that user will need more than 1 GB every month? If he or she will only need it once in a while, then just add 1 GB when needed. If the user regularly uses more than 1 GB and you want to pay for Talk, Text and 2GB of data, then yes, you would need to upgrade before buying the annual option. I’d suggest you upgrade the plan to Talk Text and 2 GB on May 25, so you have the whole billing cycle to enjoy that 2GB, then make the annual payment to start on June 25.