What is the general rule when trying to turn a recipe for two into a recipe for 100 let us say?

I heard that it is not just a question of just multiplying by 50, in this case for example.What is the general rule when trying to turn a recipe for two into a recipe for 100 let us say?
Multiply everything except the seasoning by 50, then season to taste.What is the general rule when trying to turn a recipe for two into a recipe for 100 let us say?
without seeing the recipe its difficult to say, but usually you would just multiply by 50
all ingredients times fifty