Hi guys,
We can do that no problem

If you go for the personal subscription and then later decide to go for the fully monty, just drop us a mail and we will send you an invoice for the balance and adjust your subscription period accordingly (ie, if you decide to change after 3 months, you would pay the balance and then we would adjust your subscription by 9 months, etc).
The only thing to mention is that the balance would be based on what ever the price is of the developer subscription at the time of upgrading.
Hope that answers your question
Cheers,
Chris