Home Loan expert advice needed !

I recently got HDFC home loan for a under construction property.

Around 60% loan is already disbursed (25L) remaining 30% is yet to be disbursed (13L) based upon demand from the builder.

Once the building is complete. I also need to get a topup loan for interior.

Now, I plan on saving 1L per month extra specially for my house/interior funds. I can accumulate this every month on my saving account which I know won't yield much (hardly 7%) but if I prepay 1L every month to house loan then I save the interest rate (8.6%) which is beneficial. 

I am confused if this will be a right apporch. Should I pre-pay house loan even though I will disburse more fund at the later stage. Or wait till entire fund is disbursed and then focus on pre-paying it at the later stage.

Options are : 

Pre-pay every month or Save it in saving account for house fund/interior at the later stage.

My preference is I don't like having liability over my head but at the same time also want to take path which is more economically beneficial to me.

Thanks for your time.