Rpg Maker Developers Group

Greetings,
I am having difficulty with a script that otherwise seems to function,

I am using the code;

<c_drop: i 31>
<c_chance: 100%>
<c_type: elemental 11>

Attempting to acquire the item when defeating an enemy using a weapon with a specific element, it was taken from the Script itself and was typed exactly as it was in script and placed in the enemy note tag as required and it's not working.

I've used the;

<c_drop: i 31>
<c_chance: 100%>
<c_type: custom>
<c_formula>
$game_switches[1] == true
<\c_formula>

Which works splendidly however it's not the one I want to use.

I've posted the Script as an attachment.

Thank You for Your consideration.

Addendum: at Shaz's request I have here the Original location. https://github.com/Trivel/MrTS_RGSS3/blob/master/Battle/Conditional_Drops.rb