What are the weight limits for each mode of use on the Graco 4Ever Extend2Fit car seat?

The car seat supports four modes: Rear-Facing 4-50 lb (1.8-22.5 kg), Forward-Facing 22-65 lb (10-30 kg), Backed Booster 40-100 lb (18.1-45 kg), and Backless Booster 40-120 lb (18.1-54 kg). Children less than 22 lb (10 kg) must use the seat rear-facing. Children over 65 lb must be in booster mode.