They are very good scores!
There's a saying that a child can do worse than his/her best on an IQ test because of a lot of factors (bad night's sleep, not enough to eat, boredom, itchy socks, etc.), but a child cannot do better than his/her best. With some caveats, this is something I pretty much believe. It is just one score on just one day, but it is one score and your DD achieved it.
Group testing tends to be much less GT-friendly than an individual IQ test with someone trained in testing GT kids, so I wouldn't be at all surprised if your DD's scores go up, not down.
Generally speaking, I wouldn't "disregard" any info about your child. Just add new stuff to the pile and keep watching. The picture will shift, but if you know the circumstances of the test, even a bad test day can add to the picture that's forming of your child.
Finally, be aware that if she scores above 145 on parts of the SB5 or the WISC (whichever she's taking), and she has achievement test scores in the same range, she may be eligible for the Davidson Young Scholars program (a.k.a. DYS). See here for details:
http://www.ditdgifted.org/Articles.aspx?ArticleID=252&NavID=0_35
