I noticed when downloading Dimension through the Command Center, if you lose your connectivity, it halts and you have to fully restart. Does the Command Center's download ability allow caching of previously downloaded data? That would save precious download time on these now-defunct Broadband connections, the FCC states are no longer Broadband. heh.
 
 
 

It appears that single file progress is lost and can't be resumed, but if a file completed then it can be validated and skipped to continue multi-file DLs. Steam does partial DLs quite nicely, but most hosts don't.
 
In some ways this is good, since it allows breaking up big monolithic DLs like the Sonar install into smaller files that then recover faster. If there is some 'magic' that C3 does with installing files in a certain order then this could be a problem for manual installers like myself.

Oh, I forgot, my reply was due to your comment about DL'ing Dimension. I've got a bunch of Instruments registered already that don't show up in the C3. Was this a new purchase or is there a way to add past purchases into the C3? Much as I don't like it much yet, I'm willing to give it a chance.