Because the first provisioning rating can be anything, we have to wait a few tournaments for it to be stable before we count it. Even if your child's real rating is that low initially, with some hardwork and proper guidance, s/he should be able to make progress quickly. At this stage, it's very easy for him/her to win a section outright, 3-0, 4-0, or 5-0, which will award him/her some significant bonus points. Therefore, jumping up 100 to 300 points in a single tournament is happening often. Your child will be able to rack up points quickly in this way if s/he doesn't give back too much in other tournaments. 500 points is very common for a good scholastic player.
Of course, you don't expect 500 a year every year. The higher his/her rating is, the more difficult it will be to move up a lot.
My daughter moved up 700 points in her first year. Recently, I have three students whose rating soared up 500 points or more in less than 8 months. Another extreme example, one girl from NJ All-Girls Chess Camp saw her rating zooming up 300 points over the weekend after the camp. The training and pep talk at the camp definitely had pumped her motivation up.