1. This is the full tracking of your parcel:

China Post Register Air Mail Tracking System
Parcel No.RL245078717CN tracking result
2016-08-02 14:44:03.0 Xiamen city 大宗parcel 集中center received
2016-08-02 16:14:28.0 Xiamen city 大宗parcel 集中center customs scan
2016-08-02 19:46:42.0 leaving Xiamen city 大宗parcel 集中center ，next station Xiamen
2016-08-04 09:07:21.0 Xiamen Transit Station export security scan
2016-08-04 09:12:15.0 Xiamen Transit Station export customs scan (domestic transit )
2016-08-05 20:19:45.0 Beijing Transit Station export security scan
2016-08-06 09:52:37.0 Beijing Transit Station export customs cleared
2016-08-06 22:17:00.0 arrive Beijing Airport
2016-08-06 23:26:19.0 leaving Beijing Airport going to next airport/seaport

2. And for the other parcel:

China Post Register Air Mail Tracking System
Parcel No.RS106680953CN tracking result
2016-08-08 11:32:30.0 佛山city Post Office parcel 集邮局 received
2016-08-08 22:20:22.0 佛山city Post Office parcel 集邮局 customs scan
2016-08-08 22:23:13.0 leaving 佛山city Post Office parcel 集邮局 ，next station 南海
2016-08-09 10:30:40.0 Guangzhou Transit Station export security scan
2016-08-09 11:44:50.0 Guangzhou Transit Station export customs cleared
2016-08-10 21:51:00.0 arrive Guangzhou Airport
2016-08-10 21:53:49.0 leaving Guangzhou Airport going to next airport/seaport

3. May I suggest you read this for Italy:
http://track-chinapost.com/China_Post_Arrival_Time_Stat.php

4. And for Customs Office in Italy, I found this statement very appropriate for any country in the World:

Customs & security delays:
Customs operates on their own schedule, and they don’t care how badly you want your package. Some places open and inspect almost everything, some don’t; some places process packages very efficiently, some do not.

With both Customs and security, if one item is suspicious, it may delay everything in the same dispatch.

5. You can find the above statement here:

I can fly to China in 24 hours! Why does a package take weeks?

Hope this help.