My question involves bankruptcy in the state of: Louisiana

I entered into a 100% chapter 13 plan that was to last 5-years with my final payment being Nov 2019. I have been on time with every payment and track my progress with the NDC website. When I look at the officially listed principal owed and divide that amount by my payment amount (less trustee fee), it appears that I will have overpaid the claims by $1600 with my July payment.

Do chapter 13 plans generally build in a margin for potential misadventure whereby this early repayment is possible?
Should I contact the trustee to discuss this with a possible early discharge or continue to make the ordered payments and be awarded a $12,000 refund when discharged?