Well to start with you don't need the SUM() function. All you need is
=A8*C8. The SUM function is for *adding*, not for multiplying.
Secondly, I guess that what you have in the cells isn't exactly what you've
seen.
If the 12 is exact, 2370.93/12 is 197.5775 and 2370.98/12 is 197.58166667.
If you are only displaying the content of your cells to 2 decimal places,
either of those would look like 197.58. If you want to see what's really
there, extend the number of decimal places in your cell formatting. If you
want to round the number before multiplying it, you can use the ROUND
function, or you could use Tools/ Options/ Calculation/ Precision as
Displayed, but the latter gives scope for confusion elsewhere.
