After getting all of the stiffeners ready to go, I pulled the tank skins out and started clecoing things together to see how it all fit. For the life of me I couldn't figure out what the "extra" strip was on the end of the skins. I searched the plans backwards and forwards and finally resolved to posting a question on VAF for help. Wellllllll.......As it turns out, these strips were removed in a previous section. I guess that's what I get for skipping straight to Section 18.