Yes, your email should be enough for the License Distributor to locate you (as it will be unique within the NVIDIA Portal) and allocate the additional purchases.
I don’t have any personal experience using Dell Digital Locker, but I’ve heard of a few issues previously. Whether these issues have been caused by Dells system, customer error with supplying incorrect details, an understanding of the system or a combination of all of them, I’m unsure.
Although this is an older post, it’s worth just having a look here for reference. Simon (from NVIDIA) details the steps required for the Dell Digital Locker, although this was when the PAK method was being used so there will be a difference here, but they should help guide you in the right direction and set expectations around processing time.
If you have a look and are still unsure about the process, it’s always worth speaking to Dell directly to help offer guidance this first time. Obviously if you have any issues or comments about the process after that, then come back to us on here and we’ll see what we can do.