How can I set a maximum days policy for a per diem expenditure category?

Summary:

My client wants to define a new expenditure type called "Working from Home", which will fall under the expenditure category "Per Diem". They want to enforce a policy regarding the maximum number of days an employee can submit in a month – for example, 10 days per month. How can I cover this requirement? Is there a workaround to implement this in the system?

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