On Sun, Dec 22, 2024 at 08:46 AM, John Woodgate wrote:

Yes, because it's quite easy, and probably cheaper, to use 2 or 3 sections of a quad opamp to make a good balanced-in/balanced-out circuit.

XSPICE models are minimalistic and designed for speed. Complex models would slow simulations to a crawl. In this case the "XSPICE way" for making a fully differential OpAmp creates a model with limitations and the odd "feature" it doesn't care if inputs or outputs are swapped.