What is the actual difference between innodb_autoinc_lock_mode 0,1,2
What replication method are you using?  Option 2 is fine with ROW based, but for STATEMENT replication your auto inc values on the slave are not guaranteed to be the same. 

Option 2 also means that your auto inc values probably won't be consecutive, but maybe that does not matter to you.

Option 1 is the default because it is the safest method with STATEMENT based replication (which I think is the default).  It is more scalable than option 0 since it only does a table level auto inc lock for bulk inserts but it still provides consecutive auto inc values with no gaps.  Some folks rely upon that behavior.

Sounds like for your use case you're fine with the setting you have selected, as long as your replication settings are OK.

Hope that helps.