Table Design - Setting 3 Decimals Rounds Down To First Decimal Then All 0s

I'm setting up a table that has several percentage fields, for which I want to display 3 decimal places in datasheet view (and later in forms and reports). I've tried to set up the fields in a variety of ways, but either I don't get a percent format, or I get 3 decimals with 2 zeros at the end. For example, 73.913% shows up as 73.900%. This, of course, causes problems in calculations, so that for a total percent field I'm getting things like 99.900% instead of 100.000%. I've tried various combinations of formatting properties for these fields (Field Size, Format, Decimal Places, and Scale) but I have yet to hit on the right one to simply display the correct value in the format of a percent.