The scenario in which the amount on the invoice for your next billing cycle reflects more employee licenses than you have at the very date of the invoice's issuing is possible even though not very likely.
This can happen as Insightful uses pro-rata to calculate the due amount on your invoice. When calculating the prorated charges and the needed adjustment to the amount on the invoice for your next billing cycle, Insightful takes into account:
the number of licenses you have at the end of your current billing cycle,
the specific period of time during which you have used licenses that were subject to changes in your current billing cycle.
So, if you have deactivated employee licenses at the very end of your current billing cycle, the due amount on your invoice for the next billing cycle will not reflect that.
For example:
Acme Company's billing cycle starts on the 1st of every month. They have used 10 employee licenses on the Productivity management price plan during the month of March.
During March they made no changes in the number of licenses they use.
April invoice
Their invoice for April will still reflect the 10 licenses they have used throughout March.
This is: 10 * $8 = $80 (USD)
On April the 1st they have deactivated 2 licenses and until the end of the month there were no other changes in the number of licenses.
May invoice
Their invoice for May will reflect:
the 8 licenses they have used throughout April (and will be using in May as well).
This is: 8 * $8 = $64 (USD)
the credit for the 2 licenses they have previously paid for but haven't actually used.
This is: 2 * $8 = $16 (USD)
So, the final due amount on their invoice for May will be:
$64 - $16 = $48 (USD)
For more information on how pro-rata works please click on this link.