User does not want the account summary to show at the bottom of invoices. But after unchecking the option Show account summary at the bottom of invoices in Global Settings > Billing, the new invoices still show an account summary.
This happens because the project-level rule Show account summary on invoice takes precedence over the global-level rule. The global-level rule only applies to the new projects you create by assigning them the project-level rule by default. Thus, you need to remove the rule at the project level so that the invoices of the project do not show an account summary. Check out this article to know more: If a rule exists at both global and project level, which one applies.