Picky: Your web page refers to "Mainland Chinese data" but the data you
are using came from Taiwanese military radar. (The data from mainland
China was not turned over until around 5 June, more than a week after
the data you plotted became available).
Also, it is useful to have a synchronization between the times of
the CVR/FDR, CAA radar, Taiwan mil radar, and Chinese radar. Page 14
of the FDR pdf has such a synchronization. With that synchronization
in mind the point that you plotted as point 5 is the point at which
the CVR stopped. The working hypothesis seems to be that the a/c did
not break up until 26 seconds after your point 5. Again bearing in
mind the synchronization, point 2 occured during what seems to have
been normal flight according to the FDR. That point was reached 31
seconds before the FDR stopped working and 19 seconds before the
acceleration anomalies began.
If your question is based on the location of the recovery of the
data recorders near point 8 then remember that part of the skin
after the break-up was tracked with a heading of around 53 degrees.