Mod effects are evaluated from top left to bottom right this ist mostly important for Elemental Combinations and Sentinel Percepts
examples:
Heat, Toxin, Electricity -> Gas (Heat + Toxin), Electricity
Toxin, Electricity, Heat -> Corrosion (Toxin + Electricity), Heat
A Helios with Investigator in the top left slot will first try to scan Targets
A Helios with Targeting Receptor in the top left slot will first try to shoot Targets
I see. thanks :)