Subheadings usually have built-in padding, so when they're at the top of a page, they might look a bit lower than the body text on the facing page. This padding is intentional and is meant to visually separate sections. Currently, it's not possible to customize the spacing or padding of subheadings in Atticus. However, if you want the body text to appear even with the subheading, you can make manual adjustments to move the text down the page.
Before making changes to the text for the Print version, keep in mind that this might affect the eBook version. If you're planning to adjust the layout of the body text by adding blank paragraphs or page breaks, consider creating a separate version for the ePub.