Changing SAT test date HELP!!!

<p>I am going to take the January SAT so I tried to register for it today.
But I realized that I missed the November SAT even though I registered for it.
And I knew that I could just change the test date by paying 26 dollars...(A lot less than paying for 50 dollars)
When I signed up for the November sat, my test center was a high school(I don't go there) that is located 30 minutes away from my house.
When I tried to change the test date today, it saids that "We're sorry, this registration is not available for a test center change" on the first page.
But I was able to change the test date so I continued the registeration.
However, on the select test center section, I could select my high school.
I'm a bit confused. It saids on the first page that I can't change the test center but why CAN I change it?
Everything went fine after and all I have to do now is the payment part.
I am kind of worried because what if on the actual test day, I went to my high school to take the test and not on the list...
Please help.</p>