Validity on H1B Transfer

[L1_to_H1]

I have 6 months of validity remaining on my H1B (in my 9th year now).  If I switch jobs and new employer applies for 3 years based on I140 from the current employer would I get 3 years (assuming all paperwork checks out)? And can the new employer keep using old I140 until the dates become current (which may never happen given the backlog!) and they redo PERM/I140 again? 

[pontevecchio]

As the law stands today, the answer is YES to all your questions.