Create a rate based on monthly Basic Salary based on Grades

Summary:

We have a requirment where the LTA amount is based on Grades. For example,

Grade A - 1.5 x Monthly Basic

Grade B - 2x Monthly Basic

Grade C - 1 x Monthly Basic

We are using Salary rates. Can we achieve this requirement using the same.
We are getting the below error

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

India NEL LTA consist of the factor based on Grade

Code Snippet (add any code snippets that support your topic, if applicable):