Correct me if I'm wrong, but it sounds like you're wanting to remove the 5th token from each data string every hour.
If this is correct, you do realize that eventually it's possible for you to not have 5 items in the string.

Additionally, earlier you were talking about replacement, now you're talking about removal. Please clarify which it is.

If it's removal that you want
Code:
alias reduce-tok5 {
  var %cnt = 1, %ttl = $hget(table,0).item
  while %cnt <= %ttl {
    .hadd -m table %cnt $deltok($hget(table,%cnt).data,5,9)
    inc %cnt
  }
}