Hmm interesting. So the point is they calculate in the moment of sale how many money in the national currency the buyer payed and from this sum they pay the tax from the profit to the goverment and the government kinda doesn't care what the price of bitcoin was in the moment of buying and in the moment of paying the tax. Well it is smart from the one side and complicated from the other. Because of as I know Russian government didn't accept any concrete law about crypto-currency regulation, so, such firms may have problems the next year when the tax from the profit for this year should be paid.