Skout Epoch and FX chrono!

This is an odd one, if I run my Epoch over my FX chrono I will get odd/spurious readings high and low the chrno is mounted on my bipod but I have tried it on the barrel with the same results, yet if run it over the LNBR chrono there reading are pretty much normal, I have done the same with another gun to test and had much less/near normal result from both, so why would the Epoch throw odd fps but only over the FX chrono?
The chrono normally sits on a small extension and sits just under the barrel.

KRAxfuV.jpg
 
This is an odd one, if I run my Epoch over my FX chrono I will get odd/spurious readings high and low the chrno is mounted on my bipod but I have tried it on the barrel with the same results, yet if run it over the LNBR chrono there reading are pretty much normal, I have done the same with another gun to test and had much less/near normal result from both, so why would the Epoch throw odd fps but only over the FX chrono?
The chrono normally sits on a small extension and sits just under the barrel.

KRAxfuV.jpg
There's settings to play with. My fx radar doesn't like some of my guns and I just need to change the return rate or the fpe setting. The new software update has simplified those choices but exacerbated the problem imho. I wish they would use the microphone to adjust the gain on the radar return and have 2 settings 600fps and above and 600 fps and below.