Steering force of the steering wheel

I have been driving my ct200h for over 8 years. I recently bought another car - BMW X5, and the steering on the BWM just feels so much lighter. I can turn the steering wheel easily with just one hand, but on the Lexus I would have a difficult time turning it single handed. And the steering feels more heavier if the car is loaded with gas or passengers. (I would say the steering is 30% heavier at full gas compared with 1/10 gas, and 100% heavier with 5 loaded passengers)

Both the Lexus and BWM should come with EPAS (Electric Power-Assisted Steering), but why there is a big difference in the steering force required for each car?