F4 Visa time depend on country of birth?

[ADCR 0]

Hello all!  So grateful for the infinite knowledge and experience found here.  I am very confused looking at F4 visa processes and timelines.  I'm a US citizen that came from Costa Rica on a fiance visa in 2014.  My wife and I are working on my the F4 visa application process to request one of my sisters to come here.  I have a few questions if anybody has experience or answers.

 

1.  I see insane processing times, but USCIS says it is estimated to take 10 months on my portal after submitting the online application.  I know this does not include the wait for an actual visa to become available.  That timeline seems to really vary and be VERY long for F4.  However, I was thinking about how Costa Rica has the diversity lottery visa there for the US and that CR is probably not a high immigration country.  Does the issuance time depend on the country of the beneficiary?

 

2. When do I do the I-864 affidavit of support?  It was not requested with the I-130.  Do I just wait until they ask for it?

 

Thanks in advance!

[Mike E 11,742]

Some countries are slower that the rest of the world. See the visa bulletin. 
 

When the case moves to NVC you will file I-864.