I'm with Loupey. I've tested my lenses and found no reason to ever shoot a wide angle at f/22 because f/16 always looks better, even when extreme DOF is needed. That goes for modern zoom lenses and old prime lenses on film. If you need to slow down your shutter speed then by all means shoot at f/22 and don't worry about it. It's not a big difference. But I don't recommend doing it for DOF. I suppose your gear could be different than mine, so testing is really the only way to know for sure.

Paul