Two different exchange rates on the same day

First I buy an AMZN stock when 1EUR=1.158664USD and later on the same day a TSLA stock when 1EUR=1.158828USD.

2018-08-05 Opening Balances
    Assets:Current account          2000.00 EUR
    Equity

2018-08-05 Money transfer
    Assets:Current account         -2000.00 EUR
    Assets:Investments:Euro
    
2018-08-08 Amazon Stock
    Assets:Investments:Euro        -1622.67 EUR @@ 1880.13 USD
    Assets:Investments:Stocks             1 AMZN @@ 1880.13 USD
    Assets:Investments:Euro           -0.50 EUR
    Expenses:Banking                   0.50 EUR
    
2018-08-08 Tesla Stock
    Assets:Investments:Euro         -322.74 EUR @@ 374.00 USD
    Assets:Investments:Stocks             1 TSLA @@ 374.00 USD
    Assets:Investments:Euro           -0.50 EUR
    Expenses:Banking                   0.50 EUR

I believe this is correct. However Ledger is reporting 1945.07 EUR worth of stocks, when the correct amount is 1945.41 EUR (1622.67 + 322.74)

$ ledger -f test.ledger -X EUR balance
         1998.66 EUR  Assets:Investments
           53.59 EUR    Euro
         1945.07 EUR    Stocks
        -2000.00 EUR  Equity
            1.00 EUR  Expenses:Banking
--------------------
           -0.34 EUR

Could it be that the problem is the exchange rate variation? If so, how to deal with it?