Charts have been improved by more accurately showing the exact time of the plotpoint as well as allowing you to select charts based on a time range as well as a timezone. These new changes are in effect for both character sheets as well as your battletag sheet.
Permanent datapoints for charts are now recorded at least once every 2hr 1 hour interval between imports. If you update a plotpoint within 2hrs an hour then your character sheet still gets updated and your last plotpoint just gets updated with the new data but a permanent plotpoint only occurs if you leave that plotpoint/import for more than 2hrs an hour.
Basically, if the last import is more than an hour then it becomes permanent.
If you're not sure how old your last plot point is then check the "Datapoint taken*1" part of the "Adventure and updates" on the left side of the character sheet.
These changes have been made to pave the way for something cool that's currently being developed.
Changed permanent datapoints to be accepted at an hourly rate - this allows a finer control of stats to be taken.