Survival Hunter Macro Help

Hello all, I am new to the forums but was thrilled to learn about this site and the macro add-ons. I have been testing extensively with the following macro provided by Michael J. on these forums.

#showtooltip Kill Shot
/console Sound_EnableSFX 0
/startattack
/castsequence reset=target Serpent Sting,null
/castsequence reset=0.3 0,0,0,0,0, Kill Shot
/castsequence reset=0.3 0,0,0,0,Glaive Toss
/castsequence reset=0.3 0,0,0,Black Arrow
/castsequence reset=0.3 0,0,A Murder of Crows
/castsequence reset=0.3 0,Explosive Shot
/castsequence reset=5 Arcane Shot,Cobra Shot,Cobra Shot
/cast [combat] Dire Beast
/petattack
/console Sound_EnableSFX 1
/script UIErrorsFrame:Clear()

I have played with reversing the order of the skills as its unclear to me the order in which the sequencing processes. It appears the order show above works bottom to top.

The problem I am having, or trying to understand is, why does Explosive Shot not fire first if I have enough focus each time I press the macro? Does the macro make sure all of the skills process in order first ? before starting over ? My latency is normally around 35-45 so I adjusted for that.

Sorry for the noob questions, just really trying to make sure I get this to work correctly.