These are taken from your credit union's configuration.  Late fees will always be disclosed as a whole dollar amount.  For example, a Flat fee of $17.50 will be shown as $18.00 and the Percentage method will be calculated based on the formula and rounded to the nearest whole dollar (for example, if your fine is 1% of current balance, then the late fee on a balance of $12,345.67 would be shown as $123).