Changing job 6 months before 6 year limit of H1b

[vm6580]

In 2015 june, my H1b will expire and I will have to go for the AC-21 extension because I have already been on H1b for 6 years
I have a I-140 approved , filled by my current employer

If i change my job now this is how I think my transition to the new company can be handled
1. Apply for premium H1b transfer. I am assuming that I will get h1b for 3 years now.
2. Once it is approved, join the new company. Have them filed my PERM which will take 8 to 10 months to get approved
3. Then file for i-140 again.

Are my assumptions correct? Do you see any errors in my plan?

[raghvi]

Is your soon to be ex employer willing to continue the I140 post your resignation or they are going to withdraw it?