Buffers can make each stage's current budget small enough, while the helper still checks every stage. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
The direct handoff is too large
Driving 6 inputs directly asks for 6 amperes, above the output limit.
6A>5A
Buffers split the load
Two buffers are input loads for the first stage, so that stage supplies 2 amperes. Each buffer then supplies 3 amperes to its own group.