I recommend not using the posting no. series on payment journals. It doesn't really provide value for bank references for cheque numbers or eft numbers.
Here is why, below is a payment journal batch with no posting no. series:
I have CHQ1 and CHQ2
When I post it without a posting series it retains that number:
That's how you should be preparing your payment journals and posting them if you need a backup reference. This is also important for the bank reconciliations you perform as the descriptions from a bank statement can match up against those document no.s
So why does the posting no. series exist?
It's not for payment journals with a specific reference to your internal documents (EFT, Checks etc.). The posting no. series is really just used when you have manual journal entries or want to use a specific sequence on posting. You may for example have 10 journal batches that multiple users are working in at the same time. They may have the same number series' for each of those. To ensure each entry is posted with a unique number and there is no overlap or data inconsistency you use the posting no. series. You may also get errors if you post out of sequence (i.e. I posted GJ002 and your batch still shows GJ001 so you get an error when posting)
Best practices?
Don't use a posting no. series for payment journals.
If you are going to use a posting no. series, I usually recommend using it for manual entries OR I recommend creating no. series' for specific purposes and assigning each of the no. series' to a batch with a specific purpose (i.e. - Payroll, Month End, Accruals etc.)
Hopefully that helps a bit,
