I have a similar situation. I was due to fly out on Friday FRA-EWR-LAX, but on the day of the flight, the first leg was delayed and then cancelled. I was able to get rerouted FRA-IAH-LAX. Both of those flights ended delayed, so I landed in LAX 3 hours and 45 minutes after the arrival time of my original itinerary.
If I understand correctly, since it was >3500km and <4 hours, I'd only receive 300 Euros compensation?
What doesn't make sense to me, is that if the original flight were not cancelled but also delayed, a >3 hour delay on a >3500km flight out of Europe would entitle a traveler to 600 Euros. Seems like a strange distinction to make.