There is no reason to waste a gcd on searing totem for aoe, the extra chain lighning will do more damage on trash than searing totem will do, obviously depending on the length of the fight. Reason is that elemental shamans now provide the 10% spellpower buff by default, it's no longer connected to your fire totems.
First off be aware that 10-13k has a 30% range (same as you would say 30 to 40k). If you have shit gear & weapons, all of them non optimized then that sounds about right.
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