H1-B petition amendment with or without file for extension and visa stamping.

Dear Experts,

I have a H1-B visa stamped with company A in 2013 and it’s valid till September 2015. Last year I moved to company B with the H1-B transfer and I did fly to US in the month of November 2014 with H1-B visa stamped from company A at the port of entry I was given the I-94 ending till the visa end date (Company A visa end date - September 2015).

Recently company B office shifted and new LCA has been approved, so the HR was trying to file for premium processing only amendment without extension (as USCIS states it accepts premium processing only for amending without extension), but the HR came back and said they can’t file for amendment as I have an I-94 valid till September 2015 so the new approved petition will also be given till September 2015. Here are some questions and request all of you for your clarifications and suggestions.

What if we file for only amending the petition for address change in premium processing will the new petition will be valid till September 2015 or the original petition date September 2017.What if the premium processing petition gets amended for the address change and valid till the original date September 2017 so can I fly to India for visa stamping as my visa expires on September 2015.Should I take a chance and fly to India for visa stamping with the old petition and new LCA will the visa stamping will be denied?In case in the visa interview if the consular ask me what is the reason for the petition is not amended so what should I answer.Apply for normal processing of amending the petition with extension and after July 27 push the petition for premium processing and when it gets approved then fly to India for visa stamping.Request you to clarify or suggest what is the best way to tackle this issue.