Normal FISH results for T13 question???

i received a positive for Trisomy 13 on my NIPT test with 11% PPV back in the beginning of may. 13 week ultrasound at MFM as well as 16 week ultrasound was normal and baby looked good. i got an amnio done right after 16 week ultrasound and my FISH results came normal. my question is an i good to relax a little? what are the odds that the microarray would show different? MFM counselor said she isnt worried but im still just scared to get my hopes up.