Uuuh. I really doubt that.
Single skill FLB = 15% + base (9% in this case)
Double skill FLB = 15% + 15% + base (usually 3% in event weapons)
Now, for example Crit has only 0.2 value, so it's like 15% + 3% + 3%.
... okay fine, it's not worthless (the Assault weapon that is) but it sure isn't impressive. Assault's value can easily be halved, so it's like... 12% vs. 12%, with the Crit pulling ahead on Grids above 100% Assault (read: all of them) but only with elemental advantage.