Create a sked with a function code of 9. Assign the time that the sked should execute. Leave the date field disabled. Take one of the holiday indexes and set the 27th or 28th of each month as a holiday. Assign that holiday index to your test code sked. Make certain that Except on Holiday is set to a value of NO for the test sked.
If a once every two week test is required, then set 2 days out of each month to be a holiday.
Setting a sked with a holiday index with the Except on Holiday value programmed as NO causes the sked to only execute on the days chosen as holidays.