AI Controlled weapons have zero spread along the Y-axis

I noticed that AI controlled weapons seemed extremely accurate sometimes, so I did some testing in a blank world. Manually controlled weapons had significantly more spread than AI controlled weapons, and AI controlled weapons were forming an odd diagonal pattern. I then repeated the test, making sure that the shots were aligned with the X, Y, or Z axes. Firing along the X or Z axis, every shot was perfectly along the Z or X axis, respectively, and along the Y axis, every shot was exactly on target (within the radius of 1 large block, at least).

The data I collected is here: https://docs.google.com/spreadsheets/d/1OLhvil07sMVQZKUUAGi7l6pSF7x3aeEEUorCcpIvtC0/edit?usp=sharing

This test was done by using large grid assault cannon turrets, though I have seen similar results with small grid assault cannon turrets and large grid artillery cannon turrets. I created a 9x9 grid of heavy armor blocks, with several layers and a long tail in the back, with a reactor exactly along the center line, fairly far in the back. The turrets were set to target power sources. The hits were measured by counting the damage dealt to the heavy armor blocks.

I have attached the worlds which I used for testing each axis.