[nnnnnnnn]

Not "less than 21k." There is no upper bound on the value. You always save money, provided you process upwards of $10k/mo.

A merchant processing 50k/month on square paying 2.75% would save money by switching to the new plan. At least, if I'm reading this correctly.

[wadetandy]

Except that merchant can't switch to the plan if they process that much, since it is limited to merchants under $250,000/year.

[nnnnnnnn]

No, it isn't limited that way. It's 0% under 250k, and reverts to the regular 2.75% if you process above those limits.