I've run into an issue in Excel 2010 where precision in percentage type cells is changing. To reproduce:

- Create two cells in A1 and B1, both with Percentage format (2 decimals) and numbers with decimals
- In a new cell, go to cell format, and change it to Percentage (2 decimals).
Enter this formula in the cell:

`=A1/B1`

The cell format will now change to Percentage with a higher precision, which seems to fit the amount of decimals required for the calculation.

Why does the precision change?