I have had a number of EU261 claims with UA, and at no time did the customer appreciation gesture negate the payment of the claim. For my first one or two I went the cautious route of waiting but now accept and make the separate claim. Like a previous posted I send it to the Customer Care e-mail as Other and then note EU 261 claim and provide the details of the flights - original arrival time at my final destination and time I ended up arriving at my final destination. Always out of the EU to the USA. It is one way with UA claims. :-)