I believe that you'll want to remove the {foldernum} variable from the Folder name field to get your desired result.
For each image ingested, this variable gets evaluated, and the image is placed into a folder where the name uses the evaluated data. So if you have images coming from different folders and {foldernum} evaluates to multiple values throughout the ingest, you'll end up with multiple folders within the "primary destination".
When the "Source directory structure" option is set to "Ignore- copy all photos into same destination", it is saying that it ignores the directory structure on the source for the ingest, but it knows nothing of what you are actually naming the folder(s) inside the primary destination, so if you use a variable like {folder num}, you are still going to get individual folders, numbered with the same number as what folder the image was in on the card.
