Bonney single open end wrench

[bunger]

I got this wrench in a box lot at the flea market. It looks like it came from the factory this way, not a later modification.
What would this stepped open end be used for? Two different size adjustment bolts/nuts on some equipment?

[bonneyman]

Since these types of wrenches were originally designed for aircraft hydraulic fittings, I'm thinking it was made to fit the two most commonly sized fasteners the mechanic would work on during the day. Either Bonney did it, or the mechanic did. I've never seen such a stepped OE before on a Bonney, so, I'm leading toward real nice end-user modification.
The larger fitting would be more near the end, with less "meat" of the wrench grabbing it. For that size fitting opening, not very much of the flat would be contacted - from the looks of it. So, I don't think it would be a high torque situation.

All just a guess.

[bunger]

It looks to be factory made to me, not a modification.
Look at the left side, the stepped side, it's thicker than the right straight side, but the tips are equal.
I would think that if it was a end user modification the sides would be equal thickness and the left tip would be narrower.

[Lostmind]

The larger , top opening is possibly for a locknut , the smaller bottom one for the main nut?