Why Insect-class gunboats counted with sloops

Did the Insect-class gunboats count as sloops under the treaty-era small-ship heading?

Yes for accounting purposes, although the Royal Navy called them gunboats rather than sloops.

A navy's type name did not always match the category used for treaty accounting. The Insect class were called gunboats rather than sloops. They nevertheless counted under the Royal Navy's small-ship or sloop heading. An administrative category and a formal ship-type label could therefore describe the same hull differently.