The reason we use Teflon hose is because the liner is impervious to most all chemicals in fuels, oils, hydraulic fluids, etc. I personally dont know all the chemical makeup of the fuels that you guys use. We do know (from another aircraft manufacturer) that 'some' hoses they were using would begin to fail after a period of time with mo gas. Time frame started about 3 years. I dont know the flight hours. BUT---dark deposits of the liner were getting into the carbs, creating a 'mess'. Inspecting the hoses found the there were crack, and small pieces of the liner missing. (Think of a mud puddle after it drys and begins to crack and shrink.)
Teflon eliminates this issue. Rotax is using Stratoflex 101 hose for the carb hoses OE on the 912 engines. The other fuel hoses were supplied by the airframe manufacturers. Aircraft Specialty and TS Flightlines spent alot of time working on a replacement package that was reliable, and did not have to undergo the 5 year replacement recommendation. Yes its is more expensive and more involved then your gas hose from auto parts store with hose clamps, but after seeing some of the hose failures that we saw, teflon was our choice.
Tom