TLI again


I want to know if studying at TLI is still a valid reason for visa-extensions ??

And if I possible extend my Visa, can I get the full 60 days extension
based on the last possible day or on the day I apllied for it.

I need to know exactely as I want to take 2 quadmester in a row
before breaking for 13 weeks.
Then I would like to do the same again.

My purpose is arriving on a 30 day landing visa, relax for some days, then start the course for 2 weeks, then going to Hongkong for a
weekend, coming back to Taiwan on a pre-arranged 60 day extendable visitor-visa, extending this 2 times with the help of TLI and after finishing the course legally leaving Taiwan within the 180 day period.
Would that be ok ?? Different suggestions ??
Would it be a problem to do the same again within a short time ??

Thanx in advance for your help,
bye Timo

If you study at a private school, like TLI, they only let you extend your visa for thirty days a time giving you 120 days in total.