The experimentation phase is the best teacher, you always learn from it.
I won't consider this as a comparison. Reason is that the passive crossovers are designed specifically for the drivers which are meant to be hooked up. It can not be and should not be used this way. If for the sake of argument i agree if they use same 18db slope at 3800Hz but still there are few things which are overlooked.
The ReVc is different in each driver and its not a fixed value but the average, secondly the impedance is directly related to the FR and power applied and also it causes a variance in crossover points. So if you were to measure the impedance throughout the FR with these passives, the FR and variance in crossover points,you would have been surprised by the actual data obtained.
I can reiterate the above last three lines if you say, but thats how it works.