Changing Embassy/POST in dropbox

I am holding H1B visa and travelling to india. My visa was valid till July 2018 and i have extension till May 2019.I need to do the Visa stamping.I am eligible for dropbox. I have a question regarding changing Emabassy/POST after submitting the fees.

I was planning to drop the documents in Bangalore,India and selected the state of residence as Karnataka. Currently in my interview waiver confirmation letter its showing the POST as Chennai. I have already submitted fees and got the reciept number.I want to change the POST to Delhi and drop the documents in bangalore. The reason for doing this is if in case they call for fingerprints or interview, i want to go to Delhi rather than chennai.

In DS160, i have selected the location of interview as Chennai.

Please let me know if can change the POST now by changing the state of residence in USAtravelDocs profile? If Yes, do i need to make the changes in DS160 as well? Has anyone did this before?