Here is how it went
My fingerprinting was originally scheduled for Modesto ASC for 05/29 at 8:00 am which was not convenient for me. So I went to Modesto ASC on 05/27 around 2:00 pm in the afternoon.. There was not a soul [applicant] waiting in there. I fancied my chances. There was no guard as well, just the employees. One of them came up to me , took my FP notice , asked me to sit and went inside. He returned in a few mins and rudely told me to come on the scheduled date and time... I requested him to accomodate me since I work in San Jose and since anyways there were no other applicants waiting .. He again rudely told me either you come on the scheduled date and time or reschedule for Modesto to another date , or reschedule to San Jose ASC. I then drove to San Jose ASC, reached there around 3:30 and oh boy what a difference in attitude there. The guard saw my FP notice and politely told me you have appt in Modesto , you want to do FP here, I said yes. He said sure , we have many people today , come on Friday at 8:00.
So I went to San Jose ASC this morning and did the FP. They never bothered that I was scheduled at Modesto ASC. Very nice and courteous staff and done in 10 mins.
So bottomline, the answer is YES, you can do FP at another ASC if it is convenient to you, BUT you may have to do it on the FP scheduled date/time on your notice. If you are lucky, they may even allow walk-in ahead of schedule.