Cascading LNAs

Hi all,

Just ran a side-by-side test with Uputronics 1090 MHz filtered preamp connected to FA antenna, shared by a Pro Stick Plus and an for an upcoming comparison.
To my surprise, Pro Stick Plus had 16% more position reports than the v.3.
Question is: why? AGC in PiAware 3.5.0, or an other reason I’m not aware of? FA staff or more knowledgeable folks please chime in, setup has been baselined with two identical dongles, variance is around 0.2%.

Any thoughts?