Normally, Content Manager will do the searching for dependencies of each asset (the "Searching" phase) that you have added to the Download Helper window fairly quickly (though it can still take a little bit ofg time if you have added a lot of assets to the Downoad Helper, as CM searches for dependencies of each asset one at a time). A little while ago (and I just tried it again), however, I added some of Dave Snow's new assets to the Download Helper and the "Searching" phase stood still. The DLS must be currently either down or slow. I also have an FCT. There is no download quota for FCT holders, as far as I know. There is one for non-FCT holders.
Regards,
Zachary.