Why does the conversion work incorrectly in the Yandex Checkout module?

Question

opencart

Module for opencart 2.1 Y.CMS does not convert currency correctly.
https://github.com/yandex-money/yandex-money-ycms-...
Tell me , where does the conversion take place in it?
PS Support claims that the module as such does not convert, but this is not true! Because we tested all parts of the site and everything rests on the module