The commission calculation on our Premiere account is based on the nominal currency amount and is USD 70.0 per USD 1 million on FX and USD 7.0 per 1 lot round turn on Metals.
This means that if you buy/sell any currency other than USD, the number of lots you bought/sold in the nominal currency need to be converted to USD in order to calculate the commission.
If your trading account currency is other than USD, then the calculated commission would then be converted into your trading account currency.
Your trading account currency is USD
You placed the following trade:
Buy 1.00 lot GBPUSD at 1.21556
This means you bought 100,000 GBP.
100,000GBP will need to be converted to USD at the GBPUSD spot exchange rate at the time of execution (1.21556): 100,000 x 1.21556 = USD 121,556.00
The commission charged on your account would then be: USD 121,556.00 x 70/1,000,000 = USD 8.51