Actually, your dish was bad - god knows how many wheels you put out off dish for as much as 1/4 of an inch.

For loose ball bearing hubs with the the cheap locknuts:

1. Have wheel in the stand BARELY loose enough to rotate axle.
2. Rotate the axle a full rotation while viewing the max and min displacement between rim and point.
3. Flip the wheel.
4. Rotate the axle a full rotation again while viewing the max and min displacement between rim and point.

If what you see is the same displacements - wheel is dished.

Why?

Locknuts for loose ball bearing axle sets are notoriously inconsistent.

If there is a serious imperfection on one locknut covering just a few degrees - you flip the wheel and don't land the axle on the opposite arms of the truing stand in the exact same position - just like that you are no longer testing the same thing.

Anytime you test symmetry - you must make certain your REFERENCES POINTS are EXACTLY the SAME when you flip - even when using a dishing tool.

Once you move on however to cartridge bearing hub sets - they will typically have alloy end caps that are pretty consistent. At that point the rotation is only needed if you have reason to believe the alloy end cap quality is crap.

But lets be really honest here.

The safest quick way to ensure your wheels are properly dished is to use a dishing tool.

=8-)