Ticket quotas are illegal, officers do not have a quota. The closest thing to a quota they might have is an "activity target". That could be hit by issuing tickets, giving out warnings, responding to calls for assistance, etc. Their boss wants to know they are doing something out there during their shift.
Another way an officer's activity is measured is community satisfaction. A lot of complaints about an officer would drive this down ... fast. Nitpicking tickets handed out near the end of each month would probably result in complaints by the public.
I have no personal knowledge of department procedures, I am not a police officer. I am a driver with 30 years experience on the roadways. I make an average number of driving mistakes throughout the month. In my experience I am no more likely (or for that matter less likely) to be pulled over near the end of the month than at any other time. Conclusion: If quotas existed the officers would be far less forgiving of my bad habits at the end of the month when they are trying to "make quota" and I should expect to receive more tickets at the end of the month.
Thirty times twelve is three hundred and sixty months of data ... suggests that officers are not more or less forgiving depending on what part of the month they are in. I could poll my family and friends, adding months of other driver's experience to the data ... the result would be the same. Good driver, lousy driver (have both in my family) ... warnings can happen at the end of the month, tickets can happen at the beginning of the month.
Sorry, the whole idea of officers having quotas is busted as far as I'm concerned.