Actually, it's more "personal choice" than contradictory really. Every one has their own (legal) way of doing this for their own reasons. Just offering you the option and the reason I choose the COGS option, even though I too qualify to just expense it.
"it would assume her 2017 BOY inventory was zero, which is not accurate."
Actually, from a paperwork/bookkeeping standpoint, not only is it accurate... it's spot on exactly perfect. Since your 2016 return has no inventory reported in the COGS section, your 2016 EOY inventory balance is zero. Therefore the only possible BOY inventory on your 2017 tax return *is* zero, since your 2017 BOY inventory must match your 2016 EOY inventory. So there is no problem with you starting to use COGS in 2017. Just be aware of the following.
If you expensed all your 2016 inventory on the 2016 return, then technically (and legally) speaking you've already deducted the cost of it. Therefore your 2017 BOY inventory would be zero.
So sell your 2016 inventory first. When you do sell it in/after 2017 you can't include it in your COGS at the end of the 2017 tax year. Doing so would be double-dipping since you already deducted that inventory as an expensed item on your 2016 taxes.
