For ratio expression, try this:
Sum({<[Division] = {'5' , '7'}, [Account] = {"602*", "601*", "604*"}, $(vSetMaxFinanceYear)>} [Incomes])
/
Sum(TOTAL {<[Division] = {'5' , '7'}, [Account] = {"602*", "601*", "604*"}, $(vSetMaxFinanceYear)>} [Incomes])
For Rank expression, try this:
Rank(TOTAL Sum({<[Division] = {'5' , '7'}, [Account] = {"602*", "601*", "604*"}, $(vSetMaxFinanceYear)>} [Incomes]), 1, 1)