Brake fluid will have a lower boiling point the longer it sits, especially since they typically come in plastic bottles. Ate helps since it's a metal container.

I sell amsoil and I don't run their brake fluid.
I only use their oil. I don't feel like any fluid company has an all in one stop for fluids.

I switch with ate blue and motul 600 for brake fluid.
Amsoil 10w-40 high zinc
And oem LSD fluid for the diff and tcase
Oem diaqueen for the tranny.