Immigrations are now stating (per card in my passport) money has to be in bank for 2 months before and 3 months after application. I reckon this is to stop agents putting money in. Same way they stopped agents doing 90 day reporting on-line- now only in person. Probably next thing is to stop agents doing driving tests by requiring passport to be shown when test is taken. I have never had a problem getting my visa based on monthly income.