Rather than trying to use the Aggregator you should be using the Adobe SCORM Packager tool that comes with the ELS. If you do not have that, try RELOAD Editor (Google it).
If I had to do what you are doing, I dould just have the quiz for each section at the end of that section's CPTX. I've not found it beneficial to separate out the quiz from the lesson that teaches the relevant concepts for that quiz. This would reduce the number of project files you need by half to only 5. You still need this many because Captivate doesn't let you have more than one full quiz in each project file.
