If you confirm that your patent is a duplicate license. Then the calculation time of the other party's claim for infringement compensation is from the date of his patent authorization, and the calculation standard will refer to the added value of your "infringing" goods.
The Supreme People's Court put forward the following three calculation methods of patent infringement damages in his Answers to Several Questions on Trial of Patent Dispute Cases:
(1) The amount of damages shall be the actual economic losses suffered by the patentee due to the infringement. The calculation method is: if the sales of infringing products (including products produced by other people's patented methods) in the market cause the sales volume of patented products of the patentee to decrease, the product of the total sales volume reduction multiplied by the profit income of each patented product shall be the actual economic loss of the patentee.
(2) Take all the profits obtained by the infringer due to infringement as the amount of compensation for losses. The calculation method is: the product of the profit obtained by the infringer from each infringing product (including products produced by others' patented methods) multiplied by the total amount sold in the market is the total profit obtained by the infringer.
(3) Take a reasonable amount not less than the patent license fee as the amount of compensation for losses.
For the above three calculation methods, the people's court may choose to apply them according to the different circumstances of the case.