Scenario:
If you are running the Banked Time Details report and looking at the Deposited Banked Hrs column to be rounded in 0.25 difference then you can use the following formula to create a new custom column.

Formula:
if((DepositedBankedHours-Floor(DepositedBankedHours))<=0.25,Floor(DepositedBankedHours)+0.15,if((DepositedBankedHours-Floor(DepositedBankedHours))>=0.25 && (DepositedBankedHours-Floor(DepositedBankedHours))<=0.5,Floor(DepositedBankedHours)+0.30,if((DepositedBankedHours-Floor(DepositedBankedHours))>=0.5 && (DepositedBankedHours-Floor(DepositedBankedHours))<=0.75,Floor(DepositedBankedHours)+0.45,if((DepositedBankedHours-Floor(DepositedBankedHours))>=0.75 && (DepositedBankedHours-Floor(DepositedBankedHours))<=0.99,Floor(DepositedBankedHours)+1,0))))