Adding the Account Plan Last Modified Date to the Account Header requires:
Assigning one Account Plan as the ‘Primary’ Account Plan
Creation of a Custom Formula Field on the Account
Adding that field to a new or existing Compact Layout.
Please Note: The field will reflect the last modified date on the Primary Account Plan only.
Set an Account Plan as Primary
In the Account Plan list, select the edit arrow and assign Primary to an Account Plan of your choice.
Create the Custom Field
Step 1. Choose the field type
Data Type: Formula
Next
Step 2. Choose output type
Field Label: AP Last updated
Field Name: SUBS_APLastUpdated
Formula Return Type: Date/Time
Next
Step 3. Enter formula
AP Last Updated (Date Time)= : TSPC__CPAccountPlan__r.LastModifiedDate
Next
Step 4. Establish field-level security
Leave as is or modify as needed
Next
Step 5. Add to page layouts
Leave as is or modify as needed
Save
Add AP Last Updated to the Account Header
Go to the Gear Icon > Setup > Object Manager > Account > Compact Layout
If the only Compact Layout is ‘System Default’
Clone the Layout and assign a new name. e.g. New Header
Or, add the new Field to an existing Compact Layout
Add the new Field to the Compact Layout
Open the new Compact Layout and click Edit. Move the Field from Available Fields to Selected Fields.
Save
Note: The Compact Layout selected as Primary is the layout that will be displayed on the Account Page.
Result:
The Primary Account Plan will update the field. If no Primary Account is selected, the field will not update