The bttm line is that become a PT SUP is a UPS career killer. PT SUP have .01% chance of being promoted it is a dead end job.
Obviously in my situation I disagree, but if you want to talk numbers let's talk numbers. What do you think the percentage of part time union workers get full time.. It's much lower than part time sups going fulltime management. You would think your union would push for more full time jobs. Don't get me wrong they pretend to, but why would your union want to keep all of you part time??