Realigning NL Codes across numerous Sage200 companies for Reporting

Our set up is 20+ individual companies in Sage 200. Through the years the NL Codes for the numerous Individual Companies have become out of sync. My understanding of S200 is – When transactions have been assigned to a NL code the NL code cannot be changed (unlike S50 where it can).

If this is the case then I require a workaround, I would like to propose that we create an additional reportable field in the Nominal Ledger and name this ‘Nominal Ledger Code’ which would appear on the below screen capture and be available for reporting purposes. This way I can ensure the consistency of Nominal Ledger Codes throughout the S200 companies.

Considering the impact on the other ledgers (EG Sales Ledger, Purchase Ledger, CashBook …… ) when selecting NL codes, I would like the new field 'Nominal Ledger Code' to be selectable, thus creating familiarity. Any new NL codes set up would require both the 'Code' and 'Nominal Ledger Code' to be populated and matched.

Repairs & Maintenance Company 1 Company 2 Company 3
Code (existing field) 6001 6025 7400
Nominal Ledger Code (new field) 6001 6001 6001
Does anyone have any other suggestions?