Communication sessions between external devices and implantable medical devices are tracked using a session value that is incremented for each new session and that is stored within the implantable medical device. Reports generated in response to authorizations and reports generated in response to data transfers are reconciled at a reconciliation node to improve the accuracy of payments collected and paid for use of the data. A second substrate includes a complementary metal oxide semiconductor device and a receiving structure made up of sidewalls that meet a conductive surface which is recessed from a first face of the second substrate.