Chaosticket, unfortunately, your lack of experience shines through in that post.
Auto FCS at the BB level suffers massive accuracy penalties.
While they are rare, there are ships that mount the same size guns (mostly as singles) on the T slots as the R slots. The pallada, the rurik for example.
Most battleships that carry T slot guns are AA anyways, and using that kind of a setup with manual FCS would be difficult to impossible to abuse. With auto FCS, ranges and spread would be so bad that it is not worth it, and range is king as a BB.