Someone Please Explain PeopleBooks "Defining and Updating Open Periods and Adjustment Periods"

GOAL = Open periods by Ledger Code+Adjustment Type to allow corporate accounting to book prior period adjustments (using Adjustment Type on journal header) without interfering with the normal accounting operations.  [NOTE:  we're not interested in using adjustment periods, for reporting reasons]

Here is what I'm struggling with = in PeopleBooks (Application Fundamentals) in the "Defining and Updating Open Periods and Adjustment Periods" section, it says "(The ledger code that closes the latest should not have an adjustment type.)".  HOWEVER, when I try to leave one of my ledger codes without an adjustment type, I receive this error "When Open period is by ledger code then adjustment type is required for every transaction type and ledger code. Missing adjustment type could corrupt the ledger data."