Good comments, I have been spraying a 10" band with my planter for years. I have, however decided that 10" is just a little too narrow, so I am going to widen them out to 15" this year. So instead saving 66% on pre-emerge, I'll only be saving 50%, still significant. Should be able to get that 16% back because I won't have to set my weeding discs quite so close and less root pruning?  My B & H cultivator is my post emerge "sprayer", creating a 100% savings on post emerge herbicide.

I feel my ridge till system has economic and agronomic advantages similar to your strip till system.

A lot of little things can add up quickly, like others have said.