But it is so frustrating.  Client comes in with window stickers showing Energy Star approved window stickers purchased and installed in 2023.  I said no, they would have qualified under 2022 standards but not under new standards.  The client was upset and called the window guy who told him it qualified and I was wrong.  I said have window guy put it in writing citing relevant rules, law, etc.  When that didn't come, the client called IRS, who said take credit.  Client doesn't get that IRS phone advice is worthless and is not listed anywhere as substantial authority.  Client thinks matter is settled and gets credit.  I  say I am going to do more research on matter and in the meantime, client calls manufacturer.  Finally, manufacturer says windows do NOT qualify.  So now I have a ticked off client over this matter and me ticked off for several reasons and knowing someone else would put the credit down while all I am trying to do is do it right.