I think Chuang Chih Yuan and the Chinese Taipei Table Tennis Association generally have the same goal of winning. However, both disagree on the method in doing that.
When Chuang said that he planned on only playing in the Paruguay Open and the singles event in the Asian Championship, I don't think it had anything to do with his age or with him being selfish and not wanting to help his team out in the team event. It's just that Chuang really wants to play and win the Paraguay Open. Chuang's WR has been dropping, and it would be very difficult for him to do well in World Tour events since he has to start in the Qualifications, which is filled with under-ranked Chinese players. Looking at the Paraguay Open's entry list, the field isn’t that strong, and Chuang has a great shot a winning and getting 1100 WR points. I also believe Chuang can increase his ranking by playing in the Asian Champs Singles event because there's a limit to the number of Chinese Players that can play, which should make it easier for Chuang to go farther in the tournament compared to the World Tours. This would not only increase Chuang's WR but will also help Taiwan's Team ranking increase in time for the 2020 World Team Championships and the Olympics.
You may all be wondering, why can't Chuang just play Paruguay Open and both the Team and Singles events in the Asian Champs? Unfortunately, he can't do that. The Paruguay Open ends on Sept. 14 at 5pm Paraguay Time, which is equivalent to Sept. 15, 4am Indonesia Time. The Team event of the Asian Champs start 12nn on Sept. 15, so there's just no way that Chuang can fly to Indonesia from Paraguay and adjust to jet lag in time for the Team Event. However, Chuang can make it to the singles event, which will only start on September 19, and this was his plan. This is the exact same reason why Ito and Hayata are not entered in the Asian Champs. Both originally planned to play in the Paraguay Open for WR points, but this meant foregoing the Asian Champs due to schedule and time zone differences.
The Chinese Taipei Table Tennis Association wants Chuang to play the team event in the Asian Champs. I can understand its point of view since Taiwan has a great chance for a Silver Medal (and maybe even Gold if they get lucky) in the Team Event given Lin Yun-Ju's rise. However, that would mean Chuang skipping the Paruguay Open for some "easy" ranking points. This would negatively affect Chuang's WR points and could hurt Taiwan's seeding next year in the team competitions.
In essence, Chuang's goal is more long term, which is the Olympics and the WTTC 2020. The Chinese Taipei Table Tennis Association's goal is more short-term, which is at least a Silver Medal in the Team Event of the Asian Champs. It won't be often that an event like the Paruguay Open will happen where a player can get a big reward of WR points in an event with a relatively weaker field of competition, so you can see why Chuang is reluctant to skip it. It also won't be often that a team competition like the Asian Champs will happen where a top contender like Japan doesn't send 2 of its 3 best players in a team event, which is why Taiwan wants to field its best team for the event and is reluctant to let Chuang skip it.
It's just really unfortunate that it had to end this way. We saw how the emphasis on WR has caused some internal conflicts within the Japanese National Team, and it has now done the same here by creating a conflict between Chuang and Taiwan's Table Tennis Association.