Currency conversion error with variable products

Dear VillaTheme team.

I am helping my friend with her WP site and we have an issue with variable products.

What is the problem:
Base currency is USD and we have several others available. If a customer selects a variation and then adds it to the cart with other products (variable or not) in cart and checkout pages figures are correct.
BUT
When a customer tries to pay for the order some variation prices are passed to the payment gateway in the base currency. We can’t figure any clues to why and what products are affected except it only happens with variations.

We also have seen double conversion (when a product is added to the cart in non-base currency and then on the checkout page THAT price gets converted second time).

Please help us to resolve the issues as we selected your product mainly because it allows defining what currency to which gateway should be routed.

Regards, Alex