Content Categories cause duplicates of topics?

Hello, I'm writing documentation for a large software package.

There are several different versions of the software being sold--the basic version doesn't have some features that are available in the high-end version.

I decided to create Content Categories for my AirHelp ouput, each representing the different software packages.  That way, users with the basic version of the program will only see topics discussing the functionality in their version, whereas those with the full-featured package can use a different content category and see all of the topics related to their version.

So, for testing, I've got three Content Categories: Entry, Mid-Level, and Premium--I'll call them A, B, and C respectively.

B contains all of A's topics, but a few additional ones.  C contains all of A's topics, and most of B's topics, but a few unique ones.  Also, B has a few topics that aren't in C.

I'm able to implement this successfully using conditional build tags, however, I'm finding that when I build the output, RoboHelp is duplicating topics that are included in each content category.  For example, all of A's topics (about 20 MB worth of content) are being copied for categories B and C.

The duplication is causing the size of my documentation to almost triple (from 25 MB to over 70MB!), because all of the topics in A are being copied into B and C's content categories, and so on.

That seems silly and an awful waste of space! Is that the correct behavior, or am I doing something wrong? I can't force users who auto-update to download three-times the size of the documentation just so they can have content categories!