False positive HER2?

I'm wondering if FISH tests are ever wrong. Mine came back with a ratio of exactly 2.0 with a copy number of 5.5 which places me at lowest of the low end of positivity for the ratio and the copy number by itself wouldn't qualify me as positive for HER-2. The FISH test was done on the core biopsy. JH says that it doesn't re-run the FISH test on the surgical biopsy if you had a positive on the core biopsy. If this just a little while back my ratio would have been considered equivocal, darn it, because the scale was different. I just don't want to get unnecessary treatment.