The public order seems to go up after capturing every wonder, not just the Zeus statue. I just saw it last night. The effect is already well-known: (1st turn) 20% , then (2nd turn) 15%, until it reduces to 0. Or it might be because I already have the Zeus statue, so every additional wonder revived this 4-turn bonus... I am not sure. Anyway, the game description of the Zeus statue is totally incorrect.

So, we don't have to recapture the Zeus statue province (Corinth?) every 4 turns - any other province with a statue will do the same.