If you add another expert license for an existing account, the new annual license will not be 12 months, but will be adjusted pro-rata to the billing period or license end date of your first license.
Example: If you purchase three licenses on the first of January and you decide to purchase five additional licenses two months later, you will only be billed for ten months of the annual cost of the five additional licenses. Thus, there is an adjustment of your new licenses to the first billing period.