Oracle Projects Integration with Internet Expenses - Release 12

We are using iExpenses to enter Project related expense reports. These expense reports will flow to Projects through Payables.

Is it mandatory to customize the Project Expense Report Account Generator as in case of Supplier Invoice Account Generator?

I read implementation guide and some other docs on internet and they mention about customizing the account generator when using the Project related Expense reports.

I created one Expense report for Project and gave the default company and account values in Expense template against the Expense type in GL account field. When I interfaced it to Payables the system by default derived the charge account from Template and employee record level. We have not customized the Account generator. The system didn't throw any error for not customizing the account generator as it does in case of not customizing the Supplier Invoice Account Generator.