Geopak Drainage Area Accumulation and Time of Concentration

In Geopak Drainage, will the software automatically accumulate separate drainage areas and time of concentrations in determining the accumulative flows for a particular system?

For instance at the beginning of the basin you have a sub-basin No. 1 with a pipe as an outlet. This portion of the system has an area A-1 and time of concentration Tc-1 resulting in a calculated flow of Q-1. Now further downstream, you have open channel from the previous pipe discussed to the next pipe that is an outlet to sub-basin No. 2. In this instance with flow being a factor of time and area the following would hold true for its flow calculations in sub-basin 2: Area=(A-1) + (A-2); Time of Concentration=(Tc-1) + (Tc-Pipe) +Tc-Openchannel); yielding a flow of Q-2. And this continues until you have developed all of the flows you want for a given drainage basin. So, moral of the story is flow (Q), is a function of time (Tc) and area (A) accumulated from sub-basins upstream. Of course there are other factors such as land surface coefficients and etc...but that's not important to my question.

Now back to my question....Will Geopak automatically accumulate this information in calculating flows as it moves downstream if the operator inputs separate drainage areas for each inlet node, or will the operator have to "stair-step" through the system including previously developed sub-basins?

To try and be more clear, I have attached a hand drawing of what I'm talking about. I'm no artist, but maybe it will get the point across if my awful attempt of wordsmithing has confused you. 

As stated in previous posts this week about Drainage, I'm new to the software and trying to learn as much about it as possible to make sure I fully understand its capabilities, kwirks, and limitations. The software looks to be awesome, but is only as good as the information put into it.

Thanks for any advice given...it will be much appreciated.

Matthew