Authnet Accept.js cannot do this and is not coded to allow for recharges. I had this problem with couple clients and I think the problem lies in the Accept.js itself not the integration. The service simply cannot do multiple charges out of one authorization.
You cannot do this with Authnet SIM either as the SIM method is web-based and customer enters CC info on Authnet site for one time charge.
You can do this with Authnet CIM but then this payment method requires X-Payments.