How to enter free text associated to an account in SAC Planning

A user enter $ 100 as a plan for a cost account.

But he needs to enter freely a detail on how he got to $ 100

Example:

ACCOUNT 100001 OFFICE MAINTENANCE Plan $100
Detail needed to keep

• Fix plumbing $ 70
• Change table $ 20
• Buy curtains $ 10

The issue is where and how to enter the last 3 lines, without creating a dimension

Comments could be an option, but I need to get a report of all comments associated to ACCOUNT 100001 by Cost Center