The reason we make use of palm after the second cast

It isn't a good idea to use that power too soon. So you don't want WoTLK Gold in the final couple of seconds you have Arcane Power to be restacking or debuffing your Arcane Blaster. This is just a few tips to min max in order to min max your damage in the burst window. And the main thing is that when you burst, you want to make sure that you have enough mana so that you can use arcane blasts and fishing for missile barrages.

It's not ideal to make use of missile barrage in two or three which isn't the best time to do a conservative rotation. So if anything do manage the management outside of the burst window to ensure that, during the burst window, you can be either using Arcane Blast fishing for missile barrage product, or at least getting up to that forest axe, and then making use of that missile barrage Croc.

The reason we make use of palm after the second cast , but not after the third is because , in Wrath of Lich King, you can't use presence of mind as well as arcane power at the simultaneously. Therefore, if you make use of palm, it also puts arcane powers on the 1.5 second delay. Therefore, if we make use of palm right after the third cast to buy WoTLK Classic Gold obtain the forest axe then we try and use the macro, everything in the macro will go off earlier than the arcane power.