What to do with tax on income in foreign currency if the exchange rate falls sharply before it is sold?

Question

Payment systems

Hello.
As far as I understand, the tax on income received in USD is calculated in rubles at the exchange rate of the Central Bank on the date of receipt to the transit account.
Example. 1000 USD came to the transit account. The Central Bank rate is 73.00, which means the tax is calculated as follows: (1000 * 73) * 0.06 = 4380.
And then the next day the dollar suddenly fell to 30. As a result, when selling the currency, instead of 73,000 r. we get only 30000 r. And the tax is still 4380 from these receipts remains? It turns out that the tax is no longer 6%, but all 14.6%?

Answer 1

And the tax is still 4380 from these receipts remains?

Yes.
It's not a tax anymore. You received the currency, paid tax on this amount (1000 * 0.06 = 60 USD of tax), now you have 940 USD left. Everything. Further, it is your right what to do with this currency. You can burn out on the exchange and sell everything for 30 rubles per dollar, you can leave this money in foreign currency. Or you can sell the currency right on the day it arrives on the account, if you are afraid that the dollar will collapse. One thing remains unchanged - the figure in USD. She was 940 after tax, and will remain so.
What you called "tax" in the last question is actually your loss, expressed in rubles, when selling the currency at a lower rate than yesterday. It has nothing to do with taxes.