Just go to the ID act and go through the forma given after the rules. you will find Form H and Form I. make use of these forms for the appropriate settlement.
Another differrence is that 12(3) is a tripartite settlement whose signatories are the worker/ union, the employer and the conciliation officer and 18 (1) is a bipartite settlement whose signatories are the worker/ union and the employer
Fredrick Castro
VP HR & IR