Groups tests like the OLSAT are not IQ tests. That just drives me nuts. Our district does that too. I was told that my dd10's WISC GAI in the 99.9th was probably due to "good guessing" b/c her CogAT score wasn't that high and proved that she wasn't gifted. We retested her on the WISC and, while the scores had moved around some, she was still gifted on that measure (and had 98th-99th percentile achievement scores on the WIAT/individual achievement).
That said, the WPPSI probably isn't going to give you as stable or great of info as an IQ test for an older child like the WISC. Given how high her WPPSI scores were, I'd be surprised if she came out not gifted at all on the WISC, though. Would the district take an IQ test in lieu of the OLSAT if you had her retested?
eta: you might want to take a look at this page from Hoagies as well:
http://www.hoagiesgifted.org/tests_tell_us.htm --
"However, a small study noted a potential problem with the OLSAT and very gifted children. While the correlation between group and individual intelligence tests is quite high for average scores, in this study that correlation almost disappeared for gifted scores. This means that while an average child will score very similarly on a group IQ test and an individual IQ test, a gifted child may not score similarly at all. And the study suggests that this group test may even result in a negative correlation for some gifted children: the more gifted the child, the lower the group ability test score!"
