Can someone explain how standard Auto-Generated Numbers work for sub customers? Like if I have 2 customers Cust0001 and Cust0002 And For Cust0001, I created 2 sub customers. And they get created with id as Cust0001-01 & Cust0001-02. Now when I create a sub-customer for the 2nd customer will it be Cust0002-01 or Cust0002-03?

Try it.

We just enabled Auto Num in Netsuite Instance, and a lot of sub customers id is not in sequence, that's why asking here.

they are in order of being added, essentially they follow internal ID path if you will

For one of the customers, there are 33 sub customers. And they are ranging from 3-145. I wanted clarity basically why they were not generated in order.

IDs are generated in order those customers are added. the parent/child relationships has nothing to do with assigning the numbers

That is for customers right? I am asking for sub customers Sorry, but can you please explain one more time.

it does not matter. when it comes to autonumbering NS does not take parent/child relationships into consideration