Yeah I decided that it'll be 6 because of that ending really pissed me off for being a horrible last episode. if there was some sort of OVA announcement for an un-aired 13th episode, then that 6 will become a 7.5, but since MAL doesn't do .5 then depending on if there is an OVA and if it was an actually good ending it'll be an 8 on MAL if not 7 if it has OVA, but it's only a decent OVA.