Are 3 huts the maximum for the iPhone version? And is that 3 huts including the 'special' hut or 3 huts plus the 'special' one?

Just trying to figure out the best way to level up 3 master builders when there don't seem to be any more huts to build(but I have 2 more building puzzles left at least). Fixing huts to level them up takes so long!