Isn't Ecole only the company that ported AC from Arcade? Wantanabe and TYPE-MOON are the ones that actually make the games IIRC.
Ecole did PC to Arcade. Beta tests were god awful, bugs everywhere and general crapiness. French Bread jumps in and saves the day, MBAC is born. Then MBAC ver A, then Ecole ports it to PS2 (probably still with French Bread's help but I'm not sure at this point) MBAC ver A2? is born. Then it's ported BACK to arcade again and ver B is born. Then they patch it a bit (byebye shion 2c, kouma 236a) and MBAC verB2 is born. Then it's ported BACK to PC and MBACPC ver B2 is born. I think T-M's only involvement was story aspect, general supervision of the project, and self insert cameos. (Nasu and Takeuchi)
Long stupid story short, Ecole sucks. Don't give them any credit.