Thanks @Fourth Wave Consulting. We've not used standard offers in our account, so presumably Netsuite omitted us from the email. I'm currently building another Commerce API/SSP checkout for one of our Sitebuilder sites and anticipate having Suitepromotions working in it in the next week or two. I'm more concerned with the EOL for Sitebuilder itself. Now I've grasped Netsuite's documentation, building content in SSPs is actually quite enjoyable. The concern is having a sensible platform within which to deploy these, without having to pay for an SCA license.