Just started watching season 4.
So in the first episode Junior said he dated Jillian for 3 months after Kris left, but also said he was dating Laura for 6 months and Kris was only gone 6 Months. So either Junior was banging both chicks at once or only actually dated Laura for 3 months before proposing
That's one that I absolutely hated about S4- the time jump, such a huge time jump. During the S3 hiatus, I was longing to see the first few days after the illegal match race, how everyone would cope with the consequences and where everyone would end up momentarily- Kris, Matt, Junior, Jillian, Dani, O. But the writers chose to jump ahead 6 months- very bad move.
As for your question, I'm not sure. That's a very good question that I too, would like to know an answer of.