Structures generating in really weird ways

Hi there!

For context, I am creating a mod that basically generates structures based on a directional dependent block placement (see Imgur link for reference)

For the absolute life of me, I can't seem to figure out why the blocks are placing in an "L" formation for South and North directions. 

This Imgur link contains all information I think would be relevant (block rotation settings, procedure etc.): https://imgur.com/a/xfRdskE

This Pastebin has the code for the procedure in charge of spawning the structure: https://pastebin.com/81QT52TN

Thank you so much for any help!