hi @Elaine89406
is the account is related to the inventory item?
if yes, the process will be complicated.
but I suggest by the most simple way to make a general journal at the end of the time monthly by doing this steps :
1. make an account that categorized in expense
2. do your transaction as usual or you can input new transaction using the new account
3. for the transaction that already recorded as COGS, you can manually reclass them by using a general journal (dr Expense account; cr COGS account), please do it the same as period you reporting e.g. monthly and not doing it in 1 sum/yearly in term to make the expense is in the same period as your report period.
hope this helps