Oops, that's a counting mistake! They are counted individually when totaling the maidens to 25 in the check list so I should also count them individually for situations like these too. I'll bump that count to 4.
I noticed after you get Draconic Mana, the message at the bottom on impregnating Crator still says you gained normal mana and shows that total instead of the new Draconic total.
