I'm not seeing how you are getting 72.

They start with 10.
Replace this with Jay's 20.
Replace it with 20+6 from the first KA for 26.
Replace it with 26+6 from the second KA for 32.
Double-Time that to 64.
Add the +4 from Swingline and Perplex for 68, but that gets capped at 67 by the Ro3.

haaaa, its because math is hard, my friend!

does it really matter at that point? i mean anything beyond 30 is unheard of before this scenario.