These limits only apply to our Free Plan, as well as the legacy Starter and Plus plans. All of our current plans are charged per extension.
Form
The limit does not apply to sub-forms (child forms). It only applies to parent forms and portals. You can add unlimited child forms.
Portal
The portal can have an unlimited amount of forms, child forms, and tables within it. Those added functionalities don't affect your usage quota. It will still be counted only as one portal.
Shared View
Shared Views are a special (login-less) version of the portal extension, so they are counted as a portal.