The MPCs themselves supports J-flow/IPFIX natively - so no need for a special card.
Regarding licensing, the advanced subscription for MPC10E includes sampled flows where the premium subscriptions allows you to do 1:1 flow exports.
For MPC7E you need either X number of S-ACCT-JFLOW-IN depending on your number of MPC7E's.
Alternate approach if you have (or plan to have) more than two MPC7E's you should go for one of these options as this will be cheaper than buying a license for each MPC.
1. If you only need sampled flows, then go for S-JFLOW-CH-MX960 + support (SVC-COR-JF-MX960)
2. If you need 1:1 flows then go for S-ACCT-JFLOW-CHASSIS + support (SVC-COR-JFLOW-CHASSIS)
I hope this answers your question.