Uh, what? So you waste like 2.5 seconds of energy? It's not that much more damage than BoK...
Actually, he's absolutely correct. It's not considered a loss at 85 energy.
Say my cast time on it is ~3.5 seconds, and my regen is 12.7 (these are both rough estimates - I'm at work). Over 3 seconds, I gain 44.45 energy. Say I'm at 85 energy, and cast the 3.5 second FoF -> that's 44.45 energy I've gained over the course of the cast, but I ended up losing 29.45 energy. Considering that Jab is 40 energy, that's not a full jab that I've lost (closer to 3/4 of one). This isn't even taking into consideration how many ticks I receive over the duration of the 3.5 seconds (which, mine average around 57k per tick, whereas my average BoK hits for 72K, just that the lost energy isn't as much as you're making it out to be.
Looking at my logs, just by using it on CD, it ended up being nearly 14% of my damage on heroic Vizier. Looking at my logs, I managed to have 5 ticks roughly every time it was cast, which for a 3.6s cast (in my logs, it was 3.599) = 1.38 ticks per second. Alternatively, you can also take the fact that 5 ticks @ an average of 57k over 3.6 seconds = 79,166 2/3 damage/second, which is still more damage than a single BoK.
Edit: I also wanted to add that that's not even taking into consideration that over those 3.6 seconds, you'd be losing damage due to using Jab in order to have the Chi to use BoK.