We are developing the option to change the rules for a trip in the new app for Flex HRM. If your company lets you choose rules, you will be able to do so directly in the app, so your subsistence allowance is calculated according to the rules that apply to your particular trip.
Some companies have several sets of rules, for example one for taxable subsistence allowance or one for trips on account. When you create a trip, your company's standard rules will be preselected, so most people will not need to change anything. If other rules apply to your trip, you will be able to change them. This means that companies that use several sets of rules can also move to the new app.
The feature applies to domestic trips in HRM Travel & Expense. We will share more information when it is released.