There are a lot of ways of setting location, but you’ve got them all jumbled up here.
You need to either call interp on tick, or use a timeline. You can’t do both 
If you using interp, then you sample the current value ( location ), and give it the target value.
If you’re using timelines, you need to figure out both ( the start point and end point ) before using the timeline. And then just keep them as constants during the process.