Paid or Plus account users who are using a public style that is not available to Basic Accounts can continue to use that style, but will not be able to edit it.
Chnaging colors, and such can be construed as editing; and this can be done through Custom Options, even if the account is expired. As long as the user doesn't switch to another layout, they can keep using it and they can modify it via Custom Options. This is also true of the next sentence. The users would not be able to create custom layers and edit those custom layers, but they will be able to modify the look via Custom Options.
And I just looked at another sentence there
Paid journals will also revert from the custom EntryPage and ReplyPage layouts back to system defaults.
Should the EntryPage/ReplyPage be clarified? These are code terms for the pages, but people may not undertsnad them, unless they have experience editing the code. "Customized comment pages will revert to system defaults", or something like that.