cnMaestro - Voucher expiration date start from the first claim

I've seen that when you create some vouchers, they start the expiration from the creation.

It will be helpful if can be choosed that they start the countdown to expiration from the first use of the code.

Exemple: I create a voucher with 2 days expiration. When the costumer claim that voucher, maybe 3 days after i give it to him, the 2 days expiration start from the first time the costumer insert the code in his device the first time.