Milesprower is right. Service Level is a pegging stat i.e if you miss the SL, it marks it down in the DB with a black mark, if it doesn't exceed the SL, you get a tick.
Changing the threshold will not change this retrospectively.
If you want to try to marry up the skillset and application service levels, you need to understand the timings.
Application 'timer' starts the second the call leaves the Master script, whereas the skillset 'timer' starts the second you 'QUEUE TO SKILLSET'.
Depending upon how you build your scripts, or how busy your call centre is, there may be a few seconds between these two timers e.g. your primary app may have an message that all customers must listen to.
We had an area with a similar requirement and we set the skillset threshold (which they monitored vis web client displays on plasma screens) at e.g 20 seconds, but the application threshold at 23 seconds.
This was because when they were both set the same, their RT displays would suggest they were meeting service levels, but the next day their historical stats showed they weren't.
DD