In my case, I've been working out for 4 weeks. I know I can't do a pull up yet, so I'm doing level 3 without trying level 4.
It's normal that u have to stay in a level for a few time, so for not consider it repeated change some exercise for example on Monday and Friday I do regular crunches but on Wednesday I do Lower back crunches
Like Hayden say, I don't think that the program consist only in advanced as quickly as you can through the level. If you have to stay in one until move forward to the next one, don't worry, it's normal