Rounding Dollar Amounts

Hello Everyone,

I'm using the following on a form in my database:

=(-Int(-Sum((IIf([LineTaxExempt]=Yes,(([Qty]*[Price])+([ShippingHandling])),
((([Qty]*[Price])+[ShippingHandling])*1.06))*100))))/100

In this case, I want to calculate a total for an order. If the
LineTaxExempt field is checked (meaning tax exempt), the total is
figured by the ([Qty] field X [Price] field)+the [ShippingHandling]
field.

If the LineTaxExempt is not checked, then the above total, including
shipping, is multiplied by 6% sales tax or 1.06. I then want this
value rounded up to 2 decimal places. This control is a running total
of the order.

This works most of the time, but I have run into a few rounding errors.

For example:

With exempt checked

1(Qty)X27.90(Price) + 6.44(ShippingHandling) gives me $34.35
instead of $34.34

With tax exempt checked (and multiple lines)

2(Qty)X141.02(Price) + 0.00(ShippingHandling)
10(Qty)X4.12(Price) + 0.00(ShippingHandling) gives me a
grand total of $323.25 instead of $323.24

It's frustrating because it seems like it works part of the time and
rounds wrong the other part of the time. By "rounds wrong", I mean I
set it wrong to round.

Is there a better formula to use in a form or query to round up to 2 decimal places other than the
=-Int(-Sum([Fieldname]) * 100) / 100 method that will give me the right results?

Any help/examples would be greatly appreciated on how to
modify this to give me the correct result each time.

Here are my field types:

QTY
-------
Field: Double
Format: Standard
Decimal Places: 2

Price
----------
Format: Currency
Decimal Places: 4 (some unit prices are 4 digits--Example $1.2525)

ShippingHandling
-------------------------------
Format: Currency
Decimal Places: 2

Thanks,

-Chad