Powder And Special Powers Question

im a little confused about the instruction on the third chapter of the powder book

in the second paragraph it says "Two or more like-elemental are neccesary for special abilities".
by that does it mean that i need 2 of the same colored t4-t6 powder on a weapon to acquire the special ability or do i just need 1 t4 and any other powder of the same color?

 

You'll need two or more of the same powder above Tier 3 in order to gain it's special effect. E.g. air powder 5 + air powder 5 will give you the special effect, while thunder powder 4 and earth powder 4 will not give either of the powder's effects.