The practical margin around treaty displacement

How far could a treaty warship exceed its declared tonnage before the overrun counted as cheating?

A rough tolerance was about ten percent, though the political meaning depended on how the excess was declared and used.

Wichita's excess over the nominal 10,000-ton cruiser limit raises the question of when an overrun became cheating. A practical allowance was roughly ten percent either way. That tolerance reflects the difficulty of translating a paper displacement into a completed warship. It also helps distinguish routine design growth and accounting latitude from a deliberate attempt to evade the treaty system altogether.