Actually, the calendar is showing $466.31, but the base on your flights are $466.00, so it is not actually the same as base.
There is a $466.31 total fare option, but you have to use Google Flights to bring it up - DL8276 + DL8466. It's a BE fare on AF operated codeshare flights with a fare code of VH5X87B4. The base fare on these are $342.00. The DL search doesn't show it as an option (it only has main cabin fares for those flights) probably cause they shouldn't be selling BE on AF operated flights.