Issue in Generating BILL NUMBER

Hi All,

I am facing an issue while generating the BILL NUMBER.
Issue is - when we create new BILL, it is skipping one number. (alternate number is getting generated)

for e.g
BILL 1 = AA/15P-000262,
BILL 2 = AA/15P-000264,
BILL 3 = AA/15P-000266

Can you please tell me why is it behaving like this. what is the mistake I am doing?

I am using the BN RULE as {r*:xml=CONSOLIDATION_TYPE/PARENT}AA/15P-{nnnnnn:start=1}. BN TYPE is CUST_BILL_NUMBER.