admikar,
All X-2 technology Sikorsky aircraft combined have at my best estimate less than 500 flight hours.
Actually, I calculated this for another project back in June. IIRC, Every Tilt Rotor design has flown more hours than all X2 aircraft combined. In fact, you have to add the S-69's (which was a design that eventually evolved into X2 technology) flight time to get the total flight time to reach the flight hours the V280 alone achieved. I can't easily find the flight hours for XV-15 #1 but excluding it and production V-22s that have flown for less than three years, I believe every single Tilt-Rotor airframe that ever flew has more flight hours than all X2s combined.