Infraction: 1. All posters are to make an effort to communicate clearly.
Message to User:
Don't start a new line every time you start a new sentence.
The tooltip indeed says: "[...] to reduce the cast time and mana cost of your next Lightning Bolt, [...] by 20%. Stacks up to 5 times. [...]". So a 100% reduction seems to be Blizzard's goal. And it makes sense, because then they could balance our Mana around abilities with a fixed cool down.
An interesting idea, though they could have a problem with our then free heals in PvP, but then again we'd have no mana problems with our heals (unless we don't a couple of stacks of maelstrom), but that's more of a PvP thing.
We can pretty much assume, though, that we won't get a lowered cd of LvB, so dealing with LvB will probably the break point between Shamans knowing what they do and those that have no clue.
We might see some adjustments on the mana cost of abilities then, though I guess through talents.