Entry Scenarios for Advance Entry
You can set up various scenarios for advance entry in
R/3 Travel Management via Customizing. Each of these five scenarios refers to only one method of payment of advances respectively, either cash payment via cash office or payment by check or transfer via Financial Accounting or data medium exchange.For further information on the most frequently used scenarios, see
Payment of Advances by Cash Office using Manual Posting Payment of Advances by Cash Office using Advance Data Entry Payment of Advance by Cash Office and Payment of Travel Expenses Using Data Medium Exchange Payment of Advances via Financial Accounting Payment of Advances via Data Medium Exchange 
SAP recommends that you decide to use only one of these scenarios.
In general, mixed forms can be set up via Customizing.
If you decide on using a mixed form, SAP recommends using only one method of advance payment within one employee trip.