USA A/ Xero - Previous A/R

[BellaAccounting]

I have a client who uses Xero, and when I run the balance sheet from 2017 the numbers have changed from last year.

Last year he had a negative AR of $5000 because of pre-payment that was made at the end of the year.
This year when I run the report it shows a positive $6000 for AR and a decrease in the bank balance.

The P and L is a prefect match when run again from the report run in 2017.

For the life of me I cannot find out how this happened. I have reviewed invoices, gone through AR line by line. I'm just stumped.
Any direction would be appreciated.

 

[kirby]

For both the affected A/R account and Cash accounts, run a report showing journal entry POSTING DATE and EFFECTIVE DATE (assuming the Xero system has these fields). Then look for cases where something was posted in year A but effective in Year B.
Also, see if reports have options to be printed using either effective date or posting date.
Bottom line - you will ultimately find which case is your reality as of end of 17 as the Cash acct was involved and you can determine if that transaction truly happened or did not via Bank Recon.