Frame on a cultivator needs to flex at the wing hinges so it can follow the ground. Most every one does that. Frame also needs to be able to twist front-to-back so the front outside corner can follow the dip in the ground without pulling the rear outside corner too deep or vise-versa.

Flexi-Coil 820 flexes both ways. The ability of a frame to twist, didn't used to be a big deal when you were running two ranks of shanks 2 feet from front to back. Modern cultivators have increased rank spacing to allow for better trash flow. Deeper frames make the twist deal almost a necessity for the way I farm.