What you say isn't false but on a liquid exchange there would be arbitrage opportunities (even easier to do than doing it between exchanges) so the prices should be aligned.
One would need to compare the price in EUR, USD, and the USD/EUR exchange rate at the same time to check.
Yes IF they have synchronized stats, at least across USD/EUR/BTC to make it match, but that would make the trading engine less "real time".
What you see are snapshots of a trading pair, at either a fixed rate or after n changes/timeslot, if you understand computation of values over time.
It's all granularity and deviations (Statistics... the source of many bad dreams, in my case)

@xhomerx10: thanks for that poverty guideline table!