One of the reasons why you may not have received any answers up to now, sam is that your question makes little sense without knowing, at least, what the offence is..
For some offences a six month tagging (i.e. curfew) order may be harsh, for others it may be lenient. Offenders committing a serious offence which may normally attract custody may be dealt with by way of a curfew if the circumstances of the particular incident indicate that a reduction in sentence is appropriate. Conversely some offences which may usually attract a fine may be dealt with more harshly if there are aggravating circumstances.
Percentage discounts are applied to sentences usually depending on whether a guilty plea was entered or not. A guilty plea at the earliest opportunity attracts a one third discount. However, defendants who change their plea on the day of the trial may only received five or ten percent.