CustomCalculateAmount extension for Per Diem Schedules

Hi Gurus,

We are using Per Diem schedules based with location and meals(Breakfast, Lunch and Dinner), we need a custom calculation that should calculate one of the days/one day

for 75 percent of the total reimbursable amount of line that is on demand based on additional information fields.

For Per Diem expense type additional fields would be date and yes/no fields.

1. Travel Date

2. Travel Yes/No

If I select a date, Yes. Per diem for that line date should calculate 75% of the amount. Is this possible using client extension for per diem expense type to which schedule attached.