I changed most of my fallthrough macros to priority kind and those work quiet reliably for shamans.
Code:
/castsequence reset=target Flame Shock,null
/castsequence reset=0.3 0,Lava Burst
/castsequence reset=5 Lightning Bolt,Lightning Bolt,Lightning Bolt,Lightning Bolt,Lightning Bolt,Earth Shock
The above is just an example for Lava Burst and not my complete elemental rotation.