They are re-weigh charges. I'm not sure what the time limit is, but the first weigh is $12, and re-weighs after that are $2.50 until the time runs out. Maybe 24 hours? I used the CAT scale app on my phone and it gives you the re-weigh option. It's a very convenient app for this type of thing. Doesn't do me a damn bit of good at work because of their payment processes.Badass!
Side note, how are you getting those weighs for $2.50? That’s like, 1/3 or 1/4 of what I’ve been charged