Clearing Nero Blocksize



I’ve written an application in VB6 using Nero 7.
The problem I’m have is when I finish burning my ISO to DVD, the blocksize is not clearing.
So if my first burn was 2GB and I go back and want to do another burn of different info that totals 1GB, the ISO tracksize says that the total ISO is 3GB, instead of 1GB.

So after a successful burn how do you clear the blocksize?

If this topix has already been discussed, my apologizes, I couldn’t find the topic.