Price converted wrong in cart

Hi,

I am using USD as base currency and VEF (Venezuela Bolivares) as 2nd currency. Well, the converted price in cart and checkout page is just not right, seems it converted twice, and I found the following link as resolved:

https://www.ads-software.com/support/topic/currency-conversion-is-wrong-in-cart-page/

I placed the code indicated in that, in the function.php of my current theme folder but it does not work, the problem continues what am I doing wrong?

Could you explain to me how to use that code in my web site?

Best regards,

Memento