Rule clarification

[pwinskill]

We need to clarify exactly the rules.

1. For adding interventions:

• Only one intervention can be added on top of current package in each step
• Only addition steps that lead to increased impact are considered (so cost usually will increase, but may decrease if additional intevention are cost-saving).

2. For removing interventions

• Only one intervention can be removed on top of current package in each step
• Only removal steps that are cost saving are considered (we assume that a country would not want to remove interventions if the result would be more costly overall).