Just wanted to thank y'all for answering all my questions over the months. I finally did it with success and patience and, of course, your knowledge.

11-04: Chose Delta on the portal
11-04: Less than an hour later, I went to my husband's account where he had his $100 ecredit and secured my flight. SEA > SFO comfort plus rt: $222
11-06: Grew impatient and feared I did it wrong. You fine people said I wouldn't see the coding on the app. I checked on my computer and whew, it was coded as Additional Collection. All I had to do was wait this out.
11-12: Meter moved, Travel credit posted!

Now, I just need to decide if it's worth it to keep my husband's Delta Gold Biz card for the "free" ecredit (with a $10k spend) to keep doing this or just wait for some Amex offer on my Biz Plat card to get a discount on a gift card. Decisions...

Thanks again! I was honestly amazed it worked.