Translation:My income is more than ten million in one month.
Not necessarily true though. For those who aren't salaried, you could have a very good month where you make more than ten million but make half that the next month, etc. But you might not make more than ten million each month.
Maybe the difference is "sepuluh juta sebulan" (ten million a month) vs "sepuluh juta dalam satu bulan" (ten million in one month)? I don't know whether there are slight differences in semantics, or if those two sentences mean the exact same thing...