Complicated H1 Transfer

I was working for Company A in my OPT time for 3 months. It helped me to file a H1 petition and got approved this week.
But I didn't work in past two months (August and September) since I was in the Gap (via H4).
Now Company B is willing to hire and help me to transfer H1.
My question is:
May I get reject from CIS since I don't work in Company A for a certain time?
Is that helpful that I provide my previous pay stubs (a couple of months ago, not last 3 months) from Company A?

Thanks a lot!