Some of PerfectIt’s built-in styles include subchecks. If a style includes a subcheck it is shown in the Checks dropdown below its parent check, and is indented so that it’s easy to see what’s a check and what’s a subcheck.
For example, in The Chicago Manual of Style for PerfectIt, Hyphenation of Compound Ordinals is a subcheck of Hyphenation of Phrases:
Details of how subchecks are displayed during PerfectIt’s checking can be found in Checking for More Issues.
A subcheck is displayed only for styles that include terms for that particular subcheck.
If a subcheck appears in the list of checks for the selected style, you can add terms to it as you would for any of the main checks.