Form 1040 with Sch F, farmer adds Solar to Farm Buildings. I go to Form 3468, Part VI, section B and plug in the purchase. Fix errors in Part 1 of 3468 by answering questions, get the correct credit on 3468.  Somehow credit doubles flowing to Form 3800 (60% credit now). Seems to have programing error. First question, has anyone experienced this and how do you fix it? Second Question, I still have an error for Pre-Registration Number from the IRS. Do I need to Pre-Register for a simple solar system install? Lost, please help.... Thank you....