Sales order holds during order change?

When a sales order is changed using P42101, I believe two things could happen:

• credit checking can be automatically invoked to put the order on credit hold or take the order off credit hold
• the hold code from the Customer Master could be added to the sales order header

Are both of these statements correct?

We had a situation where an order was on credit hold, but the Customer Master contained a "PY" hold.

Someone changed the amount of the sales order, which kicked off the automatic credit checking again.  Since the customer had no overdue invoices and did not have a credit limit, the order was automatically removed from credit hold.