How do you get text to appear in correct size in mobile view?

I'm using Adobe Captivate 13 and upon publish, the text does not appear correctly in mobile view. Example scenario: On a slide I have two paragraph blocks with subheader and body text. In subheader the text should be 18 px and body text 16. I have the same specs for block 2. I also have auto layout turned on for both. In preview everything looks fine. But upon publishing, my smartphone shows the subheader text is smaller than the body text for both paragraph. Another common error: the subheader text should be in bold but upon publish it shows up in regular. It's very time consuming to edit, publish, and test. Just wondering if there are rules or best practices that I’m missing. This only seems to be an issue with smartphone screen sizes because making changes and publishing in desktop view, the output is correct. What techniques have others used to correct this problem in mobile view?