Hi Jesse,
It is not difficult to get an appointment for Dr Peter Tseng as he can do the lasik for quite a number of patients per day. But sometimes he will be away for business trip. So you have to call and check his schedule.
Normally after the pre-assessment, you don't have to wait very long for the operation date. He will only perform operations for 2 to 3 days per week. The rest will be appointment for pre/post assessments. That is to say, if the next day after you do the pre-assessment is his operation day, you can do the operation next day. If not, you will have to do on next week on his operation day.