IQ scales vary from test to test. The only way to make sense of the score is to look at the percentile ranking a test's score represents. If you look at the entry requirements for organisations like Mensa, you will see different score requirements depending on the test. They require one to be in the 98% percentile on any of their approved tests.
Is that so? Tell me, which "tests vary?"
Does the WAIS vary with the Stanford-Binet? Or does Mensa use astrology to measure IQ?