Ship-number limits versus destroyer tonnage limits

What if naval treaties limited destroyer numbers rather than total destroyer tonnage?

Navies would likely exploit the gap by building many ships below the threshold, producing a larger destroyer race.

Treaty wording becomes an incentive system in this counterfactual. A cap applying only to destroyers above a stated size would leave navies free to multiply ships just below the threshold. The Royal Navy could respond by producing large numbers of sub-limit destroyers rather than accepting a true force reduction. Japan would then have a reason to answer with its own numerous general-purpose ships, creating an earlier Fletcher-like destroyer race.