There are some reasons why one would create an internal "subheading" title over creating a fresh text module (one I discovered was that we're limited to 76 modules used globally in a single Wizz, so I couldn't even create an additional "conclusion" txt module because my rapport one ranted on to the tune of 76 modules (I'm getting pretty creative with formatting and aesthetics and I use posters mainly for images)....
That said, I discovered an anomaly when trying to add a subheading. For those who don't know you can highlight the title/subheading and change the drop box to "header 3" from "paragraph" and that will give you a module title sized subheading.
What I discovered was if you bold print the subheading and do this you get a large, black/grey subtitle- nothing pretty to look at really, but if you DON'T bold print it and just leave it standalone and add the h3 (header 3) change to it what will happen is the capsule will read the pages background/layout color scheme and change the subheading to the same color as the rest of the module titles are i.e. orange background renders a red/magenta color). So if you want it to flush uniformly as a TITLE like the rest of the pages mod titles, don't bold print it and use the h3 format.