The target time of a battle is determined in part by your party's strength, but you can have up to three monster companions in your paradigm pack. How does the composition of your paradigm pack affect the party's overall strength for the purposes of determining target time?
Based on my testing, the third slot has no effect on target times.
To test this, I decided to attack the same set of monsters multiple times with different party compositions:
This is my party:
Which leads to the following totals:
I then went to Archlyte Steppe -??? AF- and walked around until I fought battles consisting only of a Goblin Chieftain and two Goblins. My target times were the following:
Thus, monster companions have no effect on target time.
As an aside, I also decided to test whether increasing Noel or Serah's power would affect the target time. Once the above tests were complete, I used 5,000 CP to increase their stats to:
For a combined total of 898 (+54 from the previous test). Testing with just Noel and Serah against a Goblin Chieftain and two Goblins, I had a target time of 1:50. So it turns out not even your party members' power affects target time.
Seemingly the game rewards high levels over strategy.