L1B Blanket extension during wife's pregnancy

[NewUser1353454]

Hi all,
My L1B blanket visa will expire in Jan2019 and my baby's delivery is due in Mar2019. From what I understand, my wife can safely travel back by first/second week of Jan. My company has agreed to file for premium extension and has already begun the documentation work. I have an important decision to take, should I file a premium extension petition by end of Nov or file for a regular extension petition by early Jan ?

My thoughts about premium processing :

• I will get a response by early January and if it's a downright rejection, I can safely travel back before it's too late for my wife
• If, for any reason, there's an RFE raised, I still get around 80 days to respond and I can still stay here till march/April
• If it gets approved, all is well

My thoughts about regular processing:

• I will have to rely on the fact that processing times are usually in months and takes a while to get through
• I don't know if it's possible, but, if for any reason, there's a rejection without RFE before March, it will be a disaster for me.

What do you suggest ?