Thanks for the info... I did a google search for delta Marriott discount and it found several FT hits (maybe just multiple pages in the same thread) and that's why I asked here.

I've never used a corporate code except for one I negotiated with a single property, and the codes listed in the sticky didn't seem to work anywhere. I was reviewing the terms on the Marriott app, so perhaps it doesn't include the full terms and conditions.

I guess the corporate code thing is one I'll continue to pass on unless I get a promo email with a code intended for me.