Number time!
According to the log, he cast LB 3 times(
Source), Lightning Bolt has a base mana cost of 6%(
source). A shaman's base mana at lvl 85 is 23430(
source). so this equals 1405.8 mana(23430 multiplied by 0.08 is in most cases 1405.8) the 3 lightning bolts he cast have thus cost 4217.4 mana(1405.8*3), or if we round the base cost up 4218 mana(1406*3).
Net gain is thus 5384(.6 if we don't round down). 5384/119602 = ~0.045 which means that he gained 4.5% more mana than he would have if he didn't cast those Lightning bolts.
Now let's look at how much we benefit from this amount of mana.
5384 mana is just under 23% of base mana ((5384/23420)*100= ~22.99%) this means 2 more extra riptides(9.4% base mana), 2 extra Healing Waves(8.48% base mana), 1 earthshield(17.86% base mana) 1 chain heal(18.8% base mana) and a variety of totems.
This might not seem much, but if you're oom just before a kill and cause a whipe, and at any point in that fight, you had the time and oppertunity to cast a few LB's, but you didn't, you're one of the reasons why you whiped.
Telluric Currents, I'd hit that.