When Clarity 16.1.1 was introduced there was the ability to add detailed rows to the cost plan. Now for SaaS customers it appears the ability has been removed.
Release : 16.1.1
It was determined by having these detailed rows in the cost plan, there was a potential to cause issues with financial reporting. Especially for custom reports and extracts.
For SaaS customers the ability has been removed.
Starting in 16.1.2, to enable the option to create child rows, go to
Classic UI > Administration > General Settings > System Options > New User Experience
uncheck option(Disable child row creation for Cost Plan Details)
Click Save.
This is documented in the Release Notes at
Bottom of this Section:
Introducing Enhancements to Financials