When you take the max of an integer array, the result is of the same integer type.
When you take the mean of an integer array, the result is (by default) double precision.
When you perform arithmetic on an integer array and a scalar double precision value, the result is of the integer type. See the "Arithmetic Operations on Integer Classes" section on this documentation page.
Convert the output of max from an integer type to double using the double function before you subtract the mean from it.
