In order to estimate the arrival time, you should take following two steps:
Get date when parcel was actually received by China Post.
You can track the parcel in traditonal track page and get following result:
Above results shows the parcel was received by China Post on April 20,2015.
You can also get result from new track page
Above results also shows the parcel was received by China Post on April 20,2015.
Go to Arrival Statistic Page and get the average arrival time from China to your country.
In above case, destination is Canada and the statistic shows average arrival time to Canada is 21 days.
So the estimated arrival time of parcel number RI422965396CN is April 20 +21 days = May 12,2015.