Oft flex fuel hardware works same as other flex kits it converts the ethanol persentage into 0 to 5v signal and this is fed ibto ecu via the re purposed evap pressure intup in ecu.
More info on how felex fuel systems work
http://www.ft86club.com/forums/showthread.php?t=120397
You then need a flex tune to interpret this signal.
The main difference is oft flex tune can only use evap input where ecutek tune can use evap or rear 02 as input.
But the flex fuel harware can be used with ecutek or oft
The oft flex kit also requores a little more installaion than most of thte say moto east or deloceois flex kits which are completly plig and play. Oft one is not overly difficult jist a little more work to install on the wiring side
See oft install video below