To answer your question: NO, you are NOT a cheapskate.
So what if the dealer was trying to take "advantage" of your circumstance? That's their job. Luckily, you were well informed of current lease rates and pricing - so you negotiated. That's a win for you!
Take this as a lesson learned that the dealer put you in a position to doubt yourself. Which, to me, is not right. I'd understand if you kicked their dog in the process but you didn't - so fcuk them.
I would not press the issue any further since they can still screw around with your ED (i.e. change dates on you, not call you when the car arrives in the US, etc.). Once you get your car back in the US and drive-off their lot, don't ever return or give them extra business :P
I've purchased/leased 4 BMWs over the years at the same dealership, nothing beats customer service and honesty. As long as you are fair and let them make some money too
Have fun on your ED, I enjoyed every minute of mine. Stock up at the free lunch cafeteria, excellent drinks and snacks! Don't forget the 12-hour rule (per bimmerfest.com), karma will get you. I ignored the rule and I curbed a rim somewhere in Europe and didn't even know it until I dropped it off in Frankfurt. Luckily my dealership processed the repair quickly, hehe.