Hi,
I am confused with your scenario. You are saying april month salary is 4206. At the time of termination his/her salary is 31,000. You just check the /113 and /112 wage type. Actually, the employee worked for 4 days so he/she should pay the ESI. We should remit the 4 days ESI to the govt. Better, you check INESI function properly.
Regards,
Vijay