PF - paid less amount than actual - What to do if I have to process that amount?

I have paid July 2018 month PF Remittance in August 2018 but by mistake I have paid less amount than actual. Difference amount is Rs. 100/- only. What to do if I have to process that amount in August 2018 month PF Remittance?
Thanks in advance for your kind support.

systemic errors goes step by step
error in ECR filing > generate arrear challan and pay now
when challan is generated for XXXX amount it goes direct debit of XXXX amount and does not accept the less amount
if you add any amount to present month, it would be treated for august only , not of july 2018

Hello,
You mean I can pay as arrears not as regular month PF remittance right?

yes, there is option to download arrears sheet, put the diff amount there against subjected UAN/s , delete the balance UAN rows, make txt file and proceed

if the remittance is short in a/c 2 then pay Rs 100/ - by direct challan but for july 18 only