My curiosity has got the best of me, and I’ll know in 2 or 3 days what they actually are ;).
Yes, MMM is the only one selling 4x 25GB Falcon BD-Rs under the SmartBlu label. They are primarily a large quantity professional market seller, and their pricing is based on this. Hence the minimum order fee.
Digistor has recently started selling 6x 25GB Falcon BD-Rs in their Digistor spindles, a good value for the price. But not quite as universally good burning among different burners as the likes of 4x Falcon, or Panasonic or Verbatim HTL discs.
What burner are you using?