Yes, that's correct. The partitioner occupies the first 15% of the install progress bar, and the copying and configuration steps occupy the rest. This was an intentional design decision: see https://wiki.ubuntu.com/UbuntuExpress/PartitioningTool under "Progress display".
** Changed in: ubiquity (Ubuntu) Status: Unconfirmed => Rejected -- Progress bars misreporting progress on filesystem creation https://launchpad.net/bugs/64556 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs