excel consulting - How do I stop the rounding up/down

Hello I have a small problem. I have to calculate signed percentages of business written. As you can see from the attachment I have a column (Written Line) which is the business percentage written per person, as you can see this column adds up to over 100%. I therefore have to sign these percentages down to 100% (ie signed line column). To do this we calculate the 100% gross divided by the overall total 175% and times by the written line amount for the individual person to get the signed line amount. I have set this to three decimal places. The overall total for this column shows 100% but if you were to actually add these amounts up on a calculator they total 100.001.

I think that because although I am showing 3 decimal places, somewhere in the background the amount of decimal places is continuous. Can you advise what I need to do to get this to calculate only three decimal places

Many thanks
Dawn


WRITTEN
LINE:
SIGNED LINE: SYND PSYD


25.00 14.286 570 ATR
25.00 14.286 727 SAM
30.00 17.143 9272 KLN
25.00 14.286 1200 BRT
16.20 9.257 2623 AFB
3.80 2.170 623 AFB
25.00 14.286 1206 GER
25.00 14.286 780 ADV

TOTAL 175.00 100.00