Yes, still recommended to wait 48 hours before paying the DUC. I assume the DUC is valid for at least a week - it wi. There have been reports of people (in 2021) trying immediately to pay and failing due to reference numbers not yet active in the system. There was one reported case of a person who paid early and the money went into limbo, DUC expired and the money returned 3 weeks later. Given the kind of chaos we’ve seen, it’s unlikely that the systems have improved since then.