From the information you have posted, I think this should be an configuration within your application.
There are a couple of ways of doing this but one of them is:
- Create a Coverage configuration entity with an attribute for the limit amount and the name
- Either create attributes for the Deductible, waiting period & co-pay or create seperate entities for them and relate them to the coverage configuration
- Now in the UI where a users enters a coverage or limit, you can retrieve the coverage configuration entity and with that do the calculations you want.
Hope this helps!