sometimes they gain a level
This has never happened, to my recollection.
Plus, I think the new system is fairly realistic, if you consider that in most firms and organizations it is normal for employees to receive periodical wage increases.
I think I've read somewhere that this happened, but I don't remember where and maybe I got it wrong.
Periodical wage increases are realistic, yes. But not monthly or weekly. Every six or three months maybe. Plus it depends a lot on the firm and organization. A sports association will combine such raises with the success the club has. As a coach for example you can not have a raise when the team you are coaching is descending. It's not justified and totally out of question isn't it?