Yeah - I think you are getting conturbulated thinking that the kinetic system (moving) is different than the static. All loads must be equal. To quicly determine the purchase of a (non-cascading) system, you can count the running lines between the two stationary points. 2 lines is 2:1, 3 lines is 3:1, 4....and so on.

If you have a cascading system, you separate the two systems and multiply them against each other. A lower block setup with 4 runs at 4:1 that attaches to a cascading system with 2 runs at 2:1 is a total of 8:1 purchase.