Here's how I would go about it...
The slate book and BATS (agency scheduling tool) changed the game in terms of how staffing and leave requests should be handled. There shouldn't be any more subjective nature to how an FLM interprets staffing. There job *should* be easy now, you're simply following a guideline.
1) Your basic watch schedule MOU should have the agreed upon minimum staffing required for each shift. Have your FacRep reiterate this to management. If leave requests are being denied, there has to be an adequate reason. Anything that requires additional staffing (ELMS, Recurrent Training, monthly meetings, etc.) should be coordinated with the Union and should be written in the shift notes. It's common courtesy and allows for people to see why their leave might be denied. Given your situation, I'm going to safely assume that since January, you'd have no problem pulling identical schedules where one leave request was approved, then another was denied with the same staffing criteria.
2) Management cannot deny leave to protect for the potential for sick leave.
3) If management will not collaborate or adhere to the shift minimum guidelines, escalate your claim via a grievance.
In large part, the FAA is removing a large portion of lowel level ATM's duties and responsibilities. With the NCEPT they can no longer give unrealistic release dates or refuse altogether and with BATS, their scheduling, prime time leave, shift guidelines, etc are all predetermined. There's simply no cognitive ability needed anymore, they are simply following an order. It is simply a flow chart like this...
Leave/Shift Swap Requested...
Minimum Staffing Met? Yes ---> Additional work needed?---->No
Approved.
