Stock on poetrade

Question about "Stock"
I want to change the stack of my chaos orbs to exalts.
I have 5000, and i want to buyer to knows, that i have that amount available..

The problem for me is that at premium currency stash the values are always rounded to 0,5.
So if i need to set 1/145 to my chaos stacks, i cant set exact price 0,069. It will change to 0,5 automaticly

But i can see other sellers somehow solve this problem, can u tell me how?