DoT renewal during an eclipse is a DPS loss. Additionally, as the GCD hard minimum is 1 second, it is impossible to renew both Insect Swarm and Moonfire in 1 second.
Originally Posted by Mythrantis
3% more damage from having Insect Swarm up during a Solar Eclipse applied to up to 11 casts, assuming latency of 100 ms, the actual minimum cast time for Wrath is 1.1 seconds due to the effect of the GCD on spell queuing. The added bonus to Wrath damage is 4.2%. 4.2% * 11 = 42% which is higher than a single 40% buff on one additional cast of Wrath, however, due to the nature of Wrath and the fact that it is an ability with a cast time and not an instant cast, by casting Insect Swarm early you are not only replacing one cast of Wrath at the start of your Eclipse, but also pushing your last Wrath off the end of Eclipse because of loss Nature's Grace. 42% damage bonus is less than 80% damage bonus of two casts.
It is always a DPS loss to renew DoTs during an eclipse.
Your technique is flawed and could account for as much as a 20% loss in overall DPS. Correcting the point in your rotation of when DoTs are renewed has led many balance druids to find gains of 1000 DPS quite easily back in tier 9.
The Lunar Eclipse case is even worse since Starfire's cast time is longer you are basically guarenteed to lose one cast of 40% more crit in order to only have around 6 casts with 4.2% more crit or a total of 25.2% more crit. 25.2% is always less than 40%.
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