Permanente: Filling out FMM ?

In my life I admit I have filled out a bunch of Mexican immigration forms, but I still have some doubts as to how to correctly fill out the FMM form as permanente. I used to fill out a new form everytime I left or returned, but last time, IMM in Mexico city insisted I should have kept the bottom portion from last time.
So if any one can clear up or confirm the following:

• As a tourist, you fill in the FMM coming in, and hand in the bottom part when you leave
  
• As a resident, it is the opposite: you fill in when you leave and keep the bottom part for your return.
  
• Do you fill both halves with your departure (flight) information, or top for departure and bottom for return?
  
• I know where to get the forms at immigration in GDL, but who do you give the top part to? Immigration or the airline?
  
• If flying out via Mexico city, can you still fill out the form in GDL?
  
• Any other relevant info is appreciated.
  

Thanks,

Pete

peteben wrote:In my life I admit I have filled out a bunch of Mexican immigration forms, but I still have some doubts as to how to correctly fill out the FMM form as permanente. I used to fill out a new form everytime I left or returned, but last time, IMM in Mexico city insisted I should have kept the bottom portion from last time.
So if any one can clear up or confirm the following:

• As a tourist, you fill in the FMM coming in, and hand in the bottom part when you leave
  
• As a resident, it is the opposite: you fill in when you leave and keep the bottom part for your return.
  
• Do you fill both halves with your departure (flight) information, or top for departure and bottom for return?
  
• I know where to get the forms at immigration in GDL, but who do you give the top part to? Immigration or the airline?
  
• If flying out via Mexico city, can you still fill out the form in GDL?
  
• Any other relevant info is appreciated.
  

Thanks,

Pete

Yes
Yes
No & Yes
They take it when you check in your baggage and get your boarding pass.
Yes, but don't give the top half to the domestic carrier, give it to the International carrier when you check in, in Mexico.
When you come back get a blank FMM so you can pre-fill before you even get to the airport the next time.