Haste for 2 ticks on Corruption:
(((9 + 2 - 0,5) / 9) - 1) * 100 = 16,66666667%
Haste - 5% (Raid Buff):
1,1666666667 / 1.05 = 1,1111111111428571428571428571429 (11,11111111428571428571428571429%)
Haste Rating:
11,11111111428571428571428571429 * 425,19 = 4724,333334683142857142857142859 (4725 Haste Rating)
http://www.wowpedia.org/Casting_speed
http://www.wowpedia.org/Haste
I missed some calculation, the formulas have changed/are wrong or is there another reason?