Bing indexed it, Google did not: what happens?
The credit comes back. The refund runs on Google alone, and a page taken by Bing does not spend it.
The table row shows it plainly: “Indexed by Google” at no, “Indexed by Bing” at yes, and the credit marked as returned.
Bing indexing is included in the same credit and checked at the same moment. You get it at no extra cost, and with no guarantee attached.