DiGi iPhone 4S RM799 Calculation

So is the new iPhone 4S promo from DiGi really a promo? See it for yourself.

Original Price = (RM88 x 24 months) + RM2090 = RM4202 (with auto-billing)
New Price = (RM138 x 24 months) + RM799 =  RM4111

Difference is only RM91.

Source: DiGi iPhone 4S