Fight or Flight reads in short E Commit: Reduce this attacked damage to it's printed damage then double it.

Someone told me you can use this E even if the attacks damage has not been raised or is even less then it's printed damage. Does that sound right?

Yes that's correct. A damage bonus is not needed to use Fight or Flight. If an attack's damage is below its printed damage, FoF will not reset the damage (because you cannot reduce upwards) but will still gain a bonus equal to the printed damage.

Ex: In an attack with 4 printed damage: FoF will make it a total of 8 damage (4+4).

Same card but its current damage is 2 instead of the printed 4: FoF will make that card 6 damage (2+4).

Stamp for Zero Cross.