Let me say it again...
You're comparing a spot instrument to a fwd instrument. It's like saying there are minor differences between the cash Spooz and the ES future. As a specific example, the spread between EURUSD spot and the front EURUSD future has varied between -1.2 and 1.7 big figures (I mean -0.012 and 0.017). The spread is extremely small and stable at the moment, because rates everywhere are so low.