Your first paragraph doesn't make sense to me.  If ending inventory is adjusted through COGS purchases, then why would state that that COGS does not factor beg and ending inventory?

Regardless, there is one right answer for actual COGS, it is basically the difference in Beg and ending inventory, plus purchases made during the year, less items removed for personal use.  I would like to see the ending inventory on balance sheet tie to ending inventory on the tax return (in Lacerte, if you prefer)