matchmaking is a complex algorithm and that's a fact. It tries to take into account so many different aspects for every player for every alliance and do the best possible match within a reasonable time frame.
What I have seen from experience is that it is greatly affected by the individual war weight a player has.
Alliances with players that have 260++ CWA bases and 300+ space age bases are doomed to have unfair matchups not because the algorithm is wrong but because the players are too late in advancing ages.
@Spaceboy if i remember correctly, you were telling us the other day that you are a high level player in lower age. So you are maxing your defences. Well, this is the price your alliance pays for playing that way.
so always remember, when you reach that minimum level for the next age, ALWAYS go for it