There is nothing funny nor ridiculous here. You are probably not used trading currency pairs. They do not move up and down like stocks. When a major currency like GBP falls 1%, it can be a significant move. A 30-40% increase in volatility on bad day could mean billions of dollars for a central bank. The one % move is not just a number against the USD but it's derived at by considering moves against other currencies like the euro and franc. I suggest you see chart of gbpusd, eurgbp, gbpchf to know what I am talking about. Good luck!!