Jet turbine reliability

I have seen various slightly different graphs from JS for ways of using their jet but consistently they predict the greatest theoretical range being from a full power climb at around 80 knots and then glide.

Next best is the economical cruise at about 75,000 rpm and around 75-80 knots - similar to the HpH scenario but JS haven't included the dolphining effect. All flight traces I have found of the JS1 jet being used for real life retrieves seem to show it being used for slow climb and cruise around 75 knots.

I am not sure if including extra range from dolphining gives a valid comparison as there is no stated model of the amount of dolphin-worthy lift being flown through. Also I would have thought that if there was enough lift to gain significant range from dolphining I would turn off the jet and get proper netto and STF info to dolphin efficiently - bearing in mind that these computations rely on the polar in the computer being the same as the glider which it clearly isn't with any engine running (even without considering prop/jetwash effects on the fin probe).