I don't know whether this will help much, but the relevant fee-fixing regulation in Queensland has -- I think -- from the year dot, set a fee for the '[transfer] of a lot or an interest in a lot'.
I suppose transfer (stamp) duty is an ad valorem tax whereas registration of a transfer or other dealing involves a service, and there is just as much work required by Titles Queensland for the transfer of an interest in a lot, as distinct from the entirety of the lot. Perhaps there will often be a bit more work for the former, in that a human brain at Titles (I assume) must check that the transferor as a severing joint, or in common, owner, has a sufficient interest to give effect to the intended transfer.
