Advanced AL as a PSE?

So I'm a PSE in my second year (PM kept me around afterall haha!). I came back in late April from my BIS and have been consistent in my hours worked since then, around 50 a week. I was talking to one of my coworkers about wanting to go camping soon so I checked my AL balance out of curiosity. It said I have earned 12 hours since my return but I had been advanced 28 hours as well bringing me to a total of 40 hours of AL available. Has anyone else heard of this? I mentioned it to a few senior clerks and they had never heard of such a thing. Is it something new? I'd like to use it if I have it but I would hate to use it only for it to be "a mistake" and have to pay it all back.