I've been interested in picking up a card with a companion cert since I travel on Delta (or make bookings for other people) around 2 - 3 times per year fairly reliably. However, without actually having a real cert code in hand, I can't run any test searches on Delta's site to see what they'd charge when using the cert vs. just buying two tickets outright at the lowest fare buckets.

Is there any trick to seeing what the fares would be if I were to use a companion cert code?

I've been searching ITA Matrix with this routing code:

This limits the search to A,I,L,U,T,X,V inventory. Is this an accurate representation of the fares that would be charged when using a companion cert, or does Delta place additional restrictions? I'm aware of the 14-day advance purchase, round-trip no open jaw, lower 48 only, and min 3 / max 30 day restrictions. Some other posts in this thread hint that there might be other requirements, but I'm having trouble teasing those out into something that I can filter through ITA.

Thanks all!