The plugin now includes several important updates.
The largest change is support for custom capabilities, or ccaps. You can now define different prorated payments when a member purchases a ccap while remaining at the same membership level. This feature was requested by a customer. The additional options make configuration more detailed, but the settings follow the site's membership structure. I can also configure them for you when necessary.
The plugin now also includes the long-planned "By Sum" prorating mode. With this addition, the available modes cover the currently identified prorating scenarios.
A new developer option can return the original s2Member® payment shortcode, like the shortcode generated on an s2Member® options page, instead of the compiled HTML form. See the plugin page for more information.