GoDaddy Web Hosting Renewal - best rates with 3 year renewals

I just figured out by chance that GoDaddy Web Hosting Renewal rates are best with 3-year renewals and not with 4 or 5-year renewals. This is a bit weird because I would expect the rates to go down with longer renewals.

From the list below, you can see that the $4.99 per month Economy web hosting plan drops to $2.99 per month with a 3 year renewal, but only drops to $3.74 per month with a 5 year renewal. Go figure!!

Note: for current GoDaddy coupons, visit: www.retailmenot.com/view/godaddy.com

Original: $4.99 plan (Economy plan)
Coupon: gda1132bp (25% off $60)

2 year renewal
Base rate: $119.76 ($4.99 per month)
- Coupon: -$29.94 (25% off)
Final rate: =$89.82 ($3.74 per month)

3 year renewal
Base rate: $143.64 ($3.99 per month)
- Coupon: -$35.91 (25% off)
Final rate: =$107.73 ($2.99 per month) (BEST RATE)

4 year renewal
Base rate: $239.52 ($4.99 per month)
- Coupon: -$59.88 (25% off)
Final rate: =$179.64 ($3.74 per month)

5 year renewal
Base rate: $299.40 ($4.99 per month)
- Coupon: -$74.85 (25% off)
Final rate: =$224.55 ($3.74 per month)