I can't remember the exact contract language or the details of the specific case that we brought, but the basic idea was that the contract assigned an hourly credit value to a day of reserve, and it also allowed us to drop reserve days. So a reserve day was worth 3.5 hours, and you'd start off scheduled for 20 days in a typical month. You'd get assigned a 30 hour credit trip the first four days of reserve that month. What's your credit now for the month? Well, 86 hours! Some pilots would keep racking up the credit and end up with 180 hour months, others (like me) would start dropping reserve days to keep the credit hours around 80 or so, but getting a lot of extra days off.
At some point management decided that this was not what they had intended in bargaining the language, so they just stopped paying it. The NPA filed a grievance, and bam! Upheld in full. Kolski, the number two guy at the company, lead contract negotiator, and former Lorenzo attorney, lost his guano, and that reserve language was basically his white whale for years.