hh:mm format to minutes.loginTime and logoutTime to minutes using the conversion function.loginTime is greater than logoutTime, add 1440 minutes (24 hours) to logoutTime to account for playing past midnight.loginTime up to the next multiple of 15 if it's not already a multiple of 15.logoutTime down to the previous multiple of 15.loginTime from the rounded logoutTime and dividing by 15.