Next time I install a mini... If there is time... I will get a flare fitting from the big box home store and compare it to the one on the mini... maybe take a close up pic and see if they are the same. Anyone who wants to do this and post the pic is welcome to do so... Would like to know if the reps are blowing smoke or not.
The box stores don't sell refrigeration flare nuts. Most of the minis I come across use metric nuts that are made from a CAST 'brass like' material and the ones from the supply house are sae sizes solid brass, and made in the USA. Never had a problem with either type.
I have however had problems with long shouldered steel flare nuts supplied on valve assemblies, replaced with brass.
Admittedly I don't use torque wrenches but do try to use flare wrenches. I still want one nonetheless.