IIRC, the 1800-1900 number is only with the P90, not the FiveSeveN.
No the 1800 to 1900 is with the Five SevenN
the P90 generates over 2100 fps with the same round.
Specifications:
Bullet Type: JHP Lead Free
Length: 40.5mm (1.6 in)
Weight of Round: 6.15 g (95 gr.)
Weight of Projectile: 1.8 g (28 gr.)
Muzzle Velocity: P90 (2132 fps) - Five-seveN (1890 fps)
Muzzle Energy: P90 (282 ft-lbs) Five-seveN (222 ft-lbs)
Source:
http://www.the-armory.com/shopsite_sc/store/html/product1210.html