What was the tax method of accounting?  Since TCJA, nothing I learned in school regarding inventory is relevant anymore.  I'm guessing that since someone was clueful enough to measure the A/P that the expenses paid with those funds were already deducted somewhere (and now have to be undeducted?)

It's hard to say anymore.  I figure at some point DIYers will all adopt the "QBO" method of accounting, where an AI just automatically categorizes everything in your bank feeds and then sends that data into a tax return.  I'm looking forward to obsolescence.