This Article describes the difference between the On-Time % completion and also the % completion and why they are often not the same or how your on-time % can be greater than you completion %.
Quick Tip- If you hover over the column headers in the report in the system it also gives the data definitions that I sometimes have to refer to as well.
This report can be a bit tricky. The two data sets don't always have the same dispatches in them. The biggest factor is the date range that is selected. For example The On-Time metric is the total % of on time completed events within the date range. Some may have launched prior to the date range. The % completion side of the report is only showing events that were opened and due within the date range and the percentage of those that have been completed. Therefore the two datasets often don't have exactly the same events. Hopefully this helps to better clarify.