i have the same question, next $8 double eight plan renewal is due to start on 19 Apr - already paid.
wonder if i can just upgrade before renewal to this $11.80 plan and pay just $3.80 balance.
I have already gotten a definitive answer from the horse's mouth. Here are the details of my correspondence with eight mobile. This should clarify all the queries and uncertainties you guys may have with regard to upgrading and downgrading plans:
I asked eight this: Let's say my $8 plan starts on 1st of every month and ends on 31st of every month, and I decided to upgrade to $18 on the 10th of this month. On the 10th, I log into my account and change my plan to $18.
Will I be paying $18, or it will be prorated to 2/3 of $18, and this new $18 plan will renew on 31st of this month?
Or will my subscription plan now be changed to start from 10th of every month and end on 9th of the following month? If so, will I get a partial refund for the $8 I paid for the initial subscription cycle of 1st-31st of the month?
Their answer: The plan upgrade will start immediately and the remaining days will forfeited.
Billing cycle will change to 10th and end on the 9th of the following month.
No refunds will be issued too.
This is only when you are doing plan upgrade. When you are doing the reverse, the change only takes effect at the end of the ongoing cycle, and not immediately when you apply for it.
Hope I have saved some of you the hassle and anxiety of guessing and speculating. Try not to upgrade too early in your current subscription cycle.