your credit report will reflect "included in wage earner plan" which is a derogatory comment. Even if you make ontime payments, I doubt they will report. As chapter 13 has no reaffirmation per say, it is up to the creditor and the reporting bureau how they list it.
I just had my scores tanked because the 3 credit bureau's changed my listing for my student loans from "deferred" to "included in wage earner plan." The comment made all 4 accounts go to derogatory and I lost 30 points across the board.
GL but I bet in the long run, the end up not reporting your on time payments.