NAT with PAT: single address pool or interface overload ?

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If I understand correctly, on Cisco routers you can configure NAT with
PAT using a single public IP address in two ways:

1) Define a pool of just one IP address. Then overload the pool with
the following command:

#ip nat inside source list 1 pool poolname overload

2) Do not use pools but just overload the interface with a public IP,

#ip nat inside source list 1 interface serial 0 overload

Am I correct ? I ask because in the additional chapter on NAT
( ) Todd Lammle doesn't mention
case 2) at all and I wonder if there is a technical reason to prefer
option 1) vs option 2).

Also, in the event a question like this pops up in the CCNA
certification sim, would both answers be considered correct ?

Finally, one last question: Does the network mask in the pool
declaration need to be precise or not ? The same Lammle changes each
time in his own chapter like this:

ip nat pool poolname


ip nat pool poolname

If it's the same, the once again how area those two going to be
evaluated by the sim software ? is it smart enough to contemplate such
cases ?

Thank you.

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