7 actions, but use of 35 durability for those 7 actions, gain of 35 durability, gain of 4 actions.

Then you use mani or MMI, and you're at 35 durability, which is 4 possible actions. You use another WNII, to make that 7 actions, gain of 3.

You could have used a 2nd MMI instead for the same gain and less CP cost, plus been able to buff your BB.