Hi jhenry,
I apologize for confusion - it's been busy today and I didn't get a chance to verify. In the Bank setup, there is an option for a separate check number sequence for manual checks. This sequence is adhered to not only for printed manual checks, but also non-printed checks.
What this means is that every time you create a new manual check, the value of the 'Next Check Number' from the Bank will be inserted into the check number field. Then the 'Next Check Number' will be incremented.
This automatic check number entry is strictly tied to the value from the bank, and not check entry itself. This means that if you change the check number from the initial value, the next check number will not increment based on the edited value. If you ever want to change the number sequence, it must be done on the bank.
Regards,