FBW A320 and Unlimited Fuel

I found out the hard way you really have to manage your fuel quantities or you’ll crash, even with the “Unlimited Fuel” selected in the sim when flying the FBW 320 on long flights.

Yesterday, somehow on a flight from NY to Miami, I completed that flight with 100% fuel quantity still available! I was glad to see that feature had worked but cannot figure out what I did nor duplicate completing a flight again without consuming any fuel.

Having unlimited fuel allows me to set up a long flight without having to be available to refuel when it’s needed.

Does anyone know how to set up unlimited fuel for this plane? Thanks for your help!

Unlimited fuel is a tick box in the assistance options

You can tell if you have unlimited fuel set up as you don’t get a maximum travel indication when applying a route.