Lead Out is pretty much the 'end' of the disc. It's there so that players know when the disc media has reached the end. How fast is your burner? My PC takes like 30 seconds to burn a lead out.
Not sure how fast it is but it's the Pioneer A06. Some DVDs take longer to "lead-out" than others. Usually record between 1x & 2X. When I'm testing on a DVD-RW, it might take me about 30 seconds to burn the tracks and then it takes about 2-4 minutes to burn the lead-out. So there must be a lot of "stuff" being written and was just curious as to what it was...