L1 to H1, H1B Visa Stamping

[gcforspouse]

I am working for the same company but moving from L1 to H1 visa. I am currently in US on L1. I94 is valid for another few months. My H1 is approved. Received I797. I will be going for stamping to my home country before I-94 expiry.

Question is does my employer need to file LCA before I go for stamping? What stage is LCA filed? Isn't it filed along with my H1B Petition? Can my H1B stamping get rejeted because my salary is below the "norm" for skilled workers?? Considering that my salary is pretty low
If LCA is not filed already and my employer needs to file it, how long does the approval process takes?

 

[sourabhm]

what should i select primary occupation

I work as software Engineer and i am on H1B. I have completed the DS-160 to apply for Visa stamping date. I saw 2 options, Engineering and Computer Science. What should i select as Primary Occupation?
If i have selected Engineering instead of computer Science, what should i do to modify ds-160?