Time Tracking in RTC

DON'T.

RTC makes a very poor timeclock. While it can be enabled (I have done it myself), it makes for a high level of overhead, and an opportunity for micromanaging. The best use of work item status is not to track a developer's time to the minute, but rather to track the status of the work item. Once a work item is started, it should stay "In progress", unless it truly gets moved to the back burner and may not get finished until a later iteration. It's better to track what is in progress and apply limits on the number of items in progress (e.g. Work In Progress limits), in order to encourage productivity. This means the team can show completed items sooner, rather than having many items in progress, but none complete. 

As far as timeclock accuracy goes, if your managers or executives are looking for this, they are likely looking in the wrong area for productivity improvements. They would be better served to look at removing impediments to the development team's work (via the Impediment or Risk work item), or looking at the Blocked Work Items query. I know the RTC devs will vouch for the efficacy of RTC's time reporting features, but I'm talking practical use of the tool, and using the right tool for the job.