function increaseOrDecreaseByHalf(vNumber, bIncrease) {
		if (typeof vNumber === "number") {
			return bIncrease ? vNumber + 0.5 : vNumber - 0.5;
		}

		vNumber = NumberFormat._shiftDecimalPoint(vNumber, 1);
		vNumber = NumberFormat.add(vNumber, bIncrease ? 5 : -5);
		return NumberFormat._shiftDecimalPoint(vNumber, -1);
	}
Adds 0.5 to or subtracts 0.5 from the given number.

@param {number|string} vNumber
  The number to be increased or decreased by 0.5
@param {boolean} bIncrease
  Whether to increase the number by 0.5; otherwise the number is decreased by 0.5
@returns {number|string}
  The number increased or decreased by 0.5; the returned type is the same as the type of the given number