Builtin round function should enable one to indicate the round precision:
Round(number, precision)
where:
Number is the value to round
Precision: number of decimal places after round (if positive), number of position to the left side of the decimal separator where to round (if negative).
Round(number, precision)
where:
Number is the value to round
Precision: number of decimal places after round (if positive), number of position to the left side of the decimal separator where to round (if negative).