I'm doing a review of the financials for a company that established their allowance account in 2018.  At the time they had a large amount of receivables past due over 60 days so the allowance was established making the entry below ($ for example purposes only):

Bad Debt                    $40k

Allowance                                  $40k

The collected almost all of the outstanding invoices during 2019.  Based on a review of the aging schedule according to the company's policy the allowance account should be ~$10k.  If I make an entry to adjust the allowance account in 2019 I will have bad debt that is negative -$30k which is unacceptable for GAAP statements.  If I use the Receivables account (which seems the logical way) then I would make the entry below:

Allowance               $30k

AR                                        $30k

Since QB requires a customer associated with JE's involving AR should I set-up an allowance customer?  Or will that screw up the AR balance?

Any advice or suggestions are welcome