What shelli said!
Results tend to be fairly stable with the same type of test. They can vary far more between different types of test, particularly between group iq tests or screeners such as the olsat (which cannot help measuring, in part, skill in multiple choice test taking) and individual iq tests, such as the WISC.
So, her olsat score will most likely remain in the same ballpark. As she has scored so high, in the 99th percentile, yes, it is likely that she will remain in the gifted range on the olsat (*you* know her scores, of course, but *I* didn't when I last posted
). With a multiple choice test you can get lucky and guess right more times than wrong, but not guess yourself in to the 99th percentile as a fluke.
Whether she will score in the gifted range or rather in the high average range on an individual iq test is another matter, but it is very likely she will score highly on that as well. Usually it works the other way round, with highly gifted kids scoring unaccountably low on the olsat because they cannot deal with the multiple choice format, recognizing complexities in the questions that the test creators did not account for.
Whether there is a point in taking a real iq test now depends on what you might need the scores for - changing into a school for the gifted, perhaps, or access to enrichment options outside of school? For the school she is currently at, it is probably a waste of time and money. As I wrote on your other thread, if they want to do something for her now, they have the sky high olsat scores to base it on.
Please check out the hoagies gifted website, tag "parents", page "testing", esp. the articles What do the tests tell us and Why do my child's scores vary from test to test?
You can spend days on that website alone, and find answers for questions you'd never have thought to ask...