Consider the circuit shown in which the currents are indicated....
Into the base of the transistors T1 flows the current IB1 = 0.1 μA. Assuming a gain βT1 = 200 results in an emitter current IC1 = 20 μA
The collector current of transistors T1 now flows into the base of transistors T2. Since the collector current is the sum of the emitter and base current, flows IB2 = 20,1 μA into the base of transistor T2.
With a gain βT2 = 200 the emitter current is IC2 = 4,02 mA...
...which is the result you measured approximately in the last experiment.