I've tested burning some data onto a DVD+RW and wanted to recover the space. However, it seems that when I use Iomega's Hotburn software to erase (whether full or fast), the old sessions are still kept. When I did a format to packet format however, I got back the entire space. However, erase after format still does not get back the entire space. (I prefer to use normal format as opposed to packet format for greater reliability.)
Is this behaviour normal? CD-RW works fine.