Visitor B2 Visa for parents after getting my Green Card

[minapee]

Update: My parents got visa on their 2nd attempt! Thanks to the almighty and all of you with your valuable opinions.

Few things I would like to mention here, if anybody is following this thread:
1. This time I have shown myself as the person paying for the journey. I have sent i-134 as well, though they did not ask for it.
2. It looks like my Green Card DO have something to do with it. Unlike lot of the posts say that they almost surely ask for 'the reason of reapplying' and 'if anything has changed for the applicant', no such questions were asked. They have wanted to know about me, how I went (F1 visa), what I am doing now etc. and asked for my immigration status documents. My parents have given them my green card copy, PP copy, job authentication letter and a pay-stub that I sent to them. No other document related to my parents were asked.
3. While nobody knows for sure how the system works, my suggestion for those who are reapplying would be to wait for several months before reapplying. Finally, even if nothing else changes for your relative, they can still get visa if something changes for you! So keep faith and give it a shot! Thank you.

At least got an idea from you. Thanks for sharing.