Visitor Visa - B2

Abbreviations:
PIL : Parents in law
MIL: Mother in law
FIL: Father in law
VO: Visa officer .

Location: Mumbai Consulate
Appointments: consecutive dates November last week.

Thanks to Immihelp for detail write up on documentation (http://www.immihelp.com/visitor-visa/sponsor-documents.html)
I wanted to invite my in-laws for my wife's graduation ceremony
My wife is enrolled for Masters degree in Public and accredited university. We got a letter form the university(which mentioned she is graduating and have planned graduation ceremony . She wants to invite her parents for graduation ceremony . PIL names mentioned in the letter from school )

My PIL had requested Hindi translator

They took travel agent help for scheduling appointment (Not required though )
My PIL did some Home-work .They met people (parents- age) with recent US visa (B2) experience and read experiences on-line (Thanks to Internet and people for sharing experience)

Day 1 : OFC appointment :

MY PIL had traveled to Mumbai and stayed with relatives .
It seems they had hard time locating the facility .
My FIL also got worried ad the speaker/microphone quality at OFC was not good, he asked and clarified that actual interview facility is nice
seems quick process

Day 2 : Interview day
(I had asked mt PIL do NOT pay attention other visa candidates)
It seems they ere able to listen to other interviews and apparently they saw 4 rejections in front of them
Actual interview :
VO(middle age american man) : Namstey
PIL (impreesed and surprised): Namstey
VO: where are you going in USA
FIL: XYZ City
VO:who is in XYZ city ?
PIL: daughetr , Son in law
VO: how long your daughter have been (Studying/Living ) in USA?
PIL: ... Thinking........
MIL: X years (My MIL has very sweet voice :) )
VO: whom do you stay with India
FIL: Son , his wife and children
VO: what does he do ?
FIL: answered :
VO: Your visa is approved .
PIL: Thank you (MIL in sweet voice :) )