Easy Chart Save Data question

If I export a small time frame, 5 hours, the time stamps align with the historical settings with a max time between records of 60 seconds.

4/27/2017 5:15 116.3971634
4/27/2017 5:16 116.4331741
4/27/2017 5:17 115.9830017
4/27/2017 5:18 116.7032776
4/27/2017 5:19 116.0730362
4/27/2017 5:20 116.7573013

If I export a large time frame, 5 days, the time stamps switch to a larger delta. In my test, 24 minutes and I’m unclear how to interpolate the data:

4/27/2017 5:15 115.2087021
4/27/2017 5:15 117.1354523
4/27/2017 5:39 115.8029251
4/27/2017 5:39 117.4055557
4/27/2017 6:03 115.3707657
4/27/2017 6:03 117.1174393

Is it showing the Min and Max value in that duration? I would have hoped it had still pulled a record every 60 seconds and am not sure why the difference.