The intriguing part here is this: What are they using, it's not ACH & it's not a Wire so it could be Check 21 (possible MyECheck licensee?), at a mere 5 cents per transaction or free if under $10. The only other option I know of is a direct debit transaction which works like a debit card.
"How is SoPayMe different than an ACH or a wire transfer? ACH Payments take multiple days to complete and can cost over 25 cents each. A wire transfer can cost over $30 each."
"How fast is the money moved? Instantly, or real-time."