Upon install, the FS2 does it's diagnostic readings and makes the adjustments accordingly. It is recommended to reset the FS2 after any adjustment to your HHO system, after the engine is warm, correct?
Now, if the HHO is injected into the system "AFTER" the MAF, how does the FS2 know there is an increase (or decrease) in HHO if there is no sensor in that location to communicate with the FS2?

Sorry if the question sounds stupid, I am not a mechanic, and the HHO system is new to me.
I just feel that after I reset my FS2 on a warm engine, my MPG seems to drop.

Can somebody please educate me?