Basically it's to free entrance for Hong Kong Airlines, Hong Kong Express, Transasia Airways, and Far Eastern Air Transport into this market.

If the increased 70 flights are correct, they are roughly 10 daily, split into half will yield 5 daily to Hong Kong carriers and 5 daily to Taiwanese carriers. If one splits even further, then the amount of flights each carrier get will dwindle even further.

As of now, for Taipei Taoyuan, China Airlines 13-14 daily, EVA 7 daily, Cathay Pacific 14-15 daily, Dragonair 3-4 daily. That yields approximately 273 flights. For Kaohsiung, as of now, Dragonair 5-6 daily, Mandarin 2 daily, China Airlines 3 daily. Approximately 77 flights.

Speaking of which, Mandarin Airlines (4 daily), Hong Kong Express (2 daily) already have services to Taichung as charters, so it's almost certain that theses rights will be used sufficiently to block new or existing carriers from taking more flights.

Probably will end up more charter flights to Hong Kong from Eastern part of Taiwan and Taichung or Kaohsiung. No carriers want to fly the other destinations unless the Taiwanese government force them.