So, finally got an e-mailed statement for that quick charge session.
Monthly Subscription Charge of Flex Plan
$0.000
DC Charging Summary
DC Charge Sessions DC Charge Duration Total DC Charging
2 Session(s) @ $4.950/session = $9.900 28 Min(s) @ $0.200000/min = $5.600 $15.500
Grand Total
$15.500