Is it possible to purchase extra submissions for just one month?

We have much heavier usage in just one or two months of the year. Is it possible to purchase extra submissions for just one month?

You can upgrade your account for one or more months, there are no limits on how many months you can upgrade for. If you would like to purchase more submissions for one month only, then please upgrade your plan and choose to pay monthly, that way you can upgrade for one month only.