TIMEDIFF('09:00', '17:00')

// returns 8

TIMEDIFF('09:00', '11:00', 'minutes')

// returns 120

TIMEDIFF('02:00', '01:00')

// returns 23

// This returns the time elapsed in the format '__ hours __ minutes'
// (or '__ hours', '1 hour __ minutes', etc.)
// Other tests:
// start_time => '03:30', stop_stop => '04:30', returns '1 hour'
// start_time => '02:15', stop_stop => '03:16', returns '1 hour 1 minute'
// start_time => '01:00', stop_stop => '01:00', returns '24 hours'

var time = TIMEDIFF('09:22', '10:09', 'minutes');
var hours = FLOOR((time / 60), 1);
var minutes = time % 60;

if ( hours < 1 && minutes < 1 ) {
SETRESULT('N/A');
}
else if ( hours == 1 && minutes < 1 ) {
SETRESULT('1 hour');
}
else if ( hours > 1 && minutes < 1 ) {
SETRESULT(hours + ' hours');
}
else if ( hours < 1 && minutes == 1 ) {
SETRESULT('1 minute');
}
else if ( hours == 1 && minutes == 1 ) {
SETRESULT('1 hour 1 minute');
}
else if ( hours > 1 && minutes == 1 ) {
SETRESULT(hours + ' hours 1 minute');
}
else if ( hours < 1 && minutes > 1 ) {
SETRESULT(minutes + ' minutes');
}
else if ( hours == 1 && minutes > 1 ) {
SETRESULT('1 hour ' + minutes + ' minutes');
}
else if ( hours > 1 && minutes > 1 ) {
SETRESULT(hours + ' hours ' + minutes + ' minutes');
}
else {
SETRESULT('');
}

// returns "47 minutes"