God damn I almost said yes.
Is it like how you can't make a HotO out of a War Scepter even though it's mace?
You would have been right to say yes

But a scepter is not a mace. Its a scepter class.
Hoto can be made in staves and maces.
It gets confusing about maces, because it does not refer to the mace class, which includes clubs/maces/hammers. It refers to maces types, so only available one is flail and its upgrades because the other 2 mace types don’t get 4+ os