Entry Type while entering online bill

Hi,

Recently I have come across two customer having similar question regarding entry type. Customer's question was Why does the billing allow a negative balance to be entered with an entry type of IN – versus a credit (CR)?

The system verifies that the entry type is the appropriate debit or credit type for the invoice amount and that the reason code corresponds to the entry type. If the combination is invalid, a warning message instructs you to click the prompt button for a list of values. This message is only a warning at the bill header level, because it is possible that the invoice amount may have changed from positive to negative when taxes were applied.