B2 Visa Renewal + Clearance Received+ Interview Waiver

I completed DS-160 for my dad for his B2 visa renewal (expires next year) and am right now on the USTravelDocs website looking for an Dropbox appointment.

My dad got his previous B2 visa in 2013 after a wait of 2 years, his visa was approved and annotated with “Clearance Received”. From what I read on this website, if you have “Clearance Received” on your visa, the USTravelDocs website will not allow you to choose an appointment for Dropbox but instead ask you to attend an interview. I answered all questions on the USTravelDocs website and surprisingly I did not see a page where it says applicant is “not qualified for visa waiver”. It walked me through all the steps and took me to the payment screen.

I’m confused. Does making a payment means he is eligible for dropbox and his interview has been waived? Or is that payment for attending an in-person interview?

Has anyone been through this situation with a visa that is annotated with “Clearance Received”? If yes, how long did it take and what did your process look like?

PS: My dad is 76 years old, if it helps to know