There is an option under Tools > Options called Precision As Displayed. Choosing this option changes the values in your cells to match the formatting of the cell.
For instance, if you have 41.234 in a cell and the cell is formatted to two decimal places (so it shows 41.23), this option will actually change the number to 41.23.
Back when I was a practicing CPA, we always had the problem of financial statements being one dollar off (the balance sheet must balance, you know). Nobody really cares about $1, but it’s just shoddy workmanship to produce a financial statement that doesn’t balance. So we would just plug a buck in somewhere and all would be well. My boss was a stickler about the Precision As Displayed option. It had to be on for financial statement workbooks or you would get a tongue lashing. Actually, he wanted it on for every workbook, but I don’t swing that way.
For financial statements, I suppose it’s not a bad policy. I’m really uncomfortable having a change in formatting change actual values. For that reason, I never use this option. I’m careful to include the ROUND function where necessary and that takes care of any problems.
Note also that the once Precision As Displayed is chosen, the actual numbers are gone forever. You can’t ever Undo them. Heed the warning.