If the "number of new licenses" matches the current subscription and the expiry is within 3 months then the order is treated as a renewal.

When you are ready to process the renewal you should just enter XXX into the number of new licenses box. This will add on XXX licenses with a new expiry date in a years time, and the existing XXX will expire on XXX.

Pricing is available at http://www.ancoris.com/ancoris-products/ancoris-signatures/ancoris-signatures-pricing.html