Robohelp html 7 to 9 upgrade issues

I've just upgraded 23 help systems from Robohelp 7 to 9.0.1.262.

Just to state up front:

My paragrah text is Arial size 10.

When the origianl help topics were written, the writers did not assign a special style to numbered steps and text in tables. They just used the "Normal" style paragraph text in tables, and when they wanted a numbered list, they applied the numbering manually.

There are specific styles for heading 1, 2, 3.

With that said, since the upgrade, I'm seeing weird formatting:

• Heading 1 in Times New Roman
• Bolded text in paragraphs that looks like extra heavy bolding.
• The spacing above and below text in tables is 14 pt. It didn't have that spacing before.
• For numbered lists, the actual number is Times New Roman, but the text is Arial.

Are these problems caused by going from html to xhtml? Does this mean that I need to make changes in the css file? Or, do I need to create specific styles for numbered lists and tables? I'm not a "super user." I've never tweeked Robohelp before.

I hope someome can help me as soon as possible?