In any cell if you enter the formula =1/3 you'll get a response
0.333333333 with as many recurring 3s as you can stand to see: widen
the cell and you'll see a ton of them, etc. The cell's value is
0.33333 with infinite recurring 3s.

You can use formatting to *display* as many 3s as you prefer, but the
cell value is 0.33333 with infinite recurring 3s unless you tell it
otherwise. For instance, you can force Excel to round to a particular
number of decimal places with the ROUND() function or one of its
variations: then, the cell's value is whatever you alter it to be.

So from what I can see you don't really have a problem: the displayed
representation of the value is one thing, but the actual cell value is
another. As a test, copy the cell in question and paste it as value
only to an unformatted cell. This will display the cell's values with
all decimal places.