Hi Tom,
Sorry we haven't gotten back with you yet. We're getting a LOT of e-mails since that review in the March AOPA Pilot magazine.
To answer your question: You will not lose the remainder of the subscription. After you purchase a year the store will automatically enable your account for exactly one year; we then have a manual step to append any remainder you might have had. We usually do this within a day or two of a subscription being purchased. This is a deficiency in our online store, which we intend to remedy somday, but it only takes a few seconds for us to manually upgrade the account and it will take many hours of programming to change this behiavior...so this change just hasn't floated to the top of my list yet.
Sorry for the confusion.
Thanks!
Walter