Code:
alias mytime {
  if ($right($time(HH:nn:ss),2) < 59) { return $left($time(HH:nn:ss),6) $+ $calc($right($time(HH:nn:ss),2) + 1) }
  else { return $left($time(HH:nn:ss),3) $+ $calc($mid($time(HH:nn:ss),4,2) + 1) $+ :00 }
}

$time = 16:54:55
$mytime = 16:54:56
$time = 16:54:59
$mytime = 16:55:00
//echo -a $time - $mytime
i tested it for once cool

new username: tidy_trax