Why is a Freespace corvette nearly the size of a destroyer? Why is a Freespace destroyer larger than a cruiser?

Seriously, I'm using a slightly different classification convention that the US Navy does. Ships are classified by role rather than by tonnage or displacement (I do have some real world examples, besides, all of this stuff is the relm of the
airforce not the navy).
Western ship classification conventions
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Cruiser - Any small, fast vessel used for escort.
Destroyer - Any escort vessel that can carry and support strike-craft.
Frigate - Any service and support ship.
Carrier - Any vessel whose primary role is to carry, service, and support strike-craft.
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Chinese ship classification conventions
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Cruiser - Any main-line combat ship. Also used to describe long range cargo, tender, or support ships.
Corvette - A fast assault ship. Essentially a bomber.
Galleon - A massive, solar-sail powered craft used to transport bulk materials within the solar system.
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I told you that
It would be done by November, well, mostly anyway...