You said you are trying to get custody of your kids. A management position will reduce the number of hours you have to spend with them.
You start earlier, maybe get of later than you do now. You may have to work some weekends also.
Your stress will increase because you no longer have to worry about just yourself, you are responsible for 30-40 others, and their actions.
I understand that your education is underutilized, but is this the best way to change that? Maybe open a business on the side where one day you can leave UPS?
Exactly what do hope to accomplish by the move, and can this be accomplished better another way?
As some posters stated, you may be put into a position where you would be pressured to compromise your ethics.
As some suggested, rushing into a life changing career choice may not be best choice now. Your feelings on things may change in a few months and burning bridges may not be in your best interest.
These are some questions to answer before you make the move.
I am not trying to talk you out of it, as management is the best thing for some people, you need to make sure that you are one of those people.
Pray on it. Talk to others who have made the choice you are contemplating. Most on cars I have spoken to, and some managers, have regretted their decision. There is a good reason for that.
Good luck to you in whatever you decide.