Yes, I've also often felt that there is confusion in the time stamps between something happening and something being reported, in other places too.  For instance, in the status.log file in the buckets.  (Which makes me guilty of not opening a similar bug earlier, but never mind---thank you for opening this.)

don - anything we can do here? nxia says some of these time stamps are controlled by build bot. 

This isn't the first time this issue has come up. The entire method that we use to render flexible steps (allowing cbuildbot to define its own structure) is a bit of a hack, and cbuildbot's employment of this method is further hacky. cbuildbot runs multiple steps in parallel, and then emits them to BuildBot with status results as each finishes. If one step has already finished, cbuildbot delays emitting it to BuildBot until all previous parallel steps have also finished so that the output is properly ordered.

However, from BuildBot's perspective, this means that the step starts and them immediately finishes, resulting in the 0 duration and immediate start/stop times. There's no simple way to fix this, and any sort of fix would require additional BuildBot hacks and cbuildbot's cooperation.

Two solutions come to mind:
1) Suppress per-step durations in BuildBot output. This is as simple as modifying the build template that BuildBot uses for ChromeOS
2) Have cbuildbot emit its times and duration explicitly as annotations.

I like seeing the times, so I'd vote for #2.

Note that they are not mutually exclusive. Combining #1 and #2 would actually still show you more accurate times without the misleading BuildBot times.

The ReportStage links out to "Build stages timeline" and "Build details" both of which present an accurate and correct timeline.

The stanza 
"started: Thu Dec 22 05:51:32 2016
ended: Thu Dec 22 06:06:07 2016
duration: 14 mins, 34 secs
status: SUCCESS"

that you see is generated by buildbot, and is incorrect because it doesn't know about stage parallelism (we have to linearize the stage history when we log it.

I like the idea of adding during to our stage completion logs, and then turning off the buildbot stuff.

IE, adding duration to:

************************************************************
** Finished Stage SetupBoard - Thu, 13 Apr 2017 14:49:54 -0700 (PDT)
************************************************************

The Legoland UI should have the correct timing in nearly all cases.