Why is the use of dates/times so difficult in mIRC?

I'm trying to find all records that have been added in the last 24 hours, but the comparison between current date/time and the one from 24 hours ago doesnt work.

Code:
alias recent-record-stats {
  var %cnt = 1
  var %tbl = records
  var %ttl = $hget(%tbl,0).item
  var %start-date = $+($calc($asctime(dd) - 1),/,$asctime(mm/yyyy))
  var %start-time = $+($calc($asctime(hh) - 2),:,$asctime(nn:ss))

  while (%cnt <= %ttl) {
    var %data = $hget(%tbl,%cnt)
    var %date = $gettok(%data,11,9)
    var %time = $gettok(%data,12,9)
    if (%start-date %start-time > %date %time) {
      do stuff
    }
    inc %cnt
  }
}


if (%start-date %start-time > %date %time) {
Does anyone know how I can get something like this to work?

Thanks in advance!