Special offer on Vredestein tyres, -4% discount...pay £4.95 more. Wtf?

http://www.camskill.co.uk/m61b0s22p111401/Vredestein_Tyres_Car_Vredestein_Ultrac_Sessanta_-_255_35_R18_94Y_XL_TL_Fuel_Eff_%3A_F_Wet_Grip%3A_C _NoiseClass%3A_1_Noise%3A_67dB