How to configure Benefits rates for Critical Illness Plan based on age and selection of option?

Summary:

We have a requirement for Benefits rates, The Critical Illness plan uses variable rate profiles based on different age bands(Age 20-30, Age 30-40, Age 40-50) so that people with different ages can pay different amounts for the same plan and option. 
When a life event is evaluated, it gives an enrollment opportunity to choose an employee from different Critical Illness plan options. As per requirement, the rate should be updated only if the employee chooses a different option than earlier, and the new rate should be as per the current age and option selected on the life event occur date. If the employee has the same option means then the rate should not be changed regardless of the current age on the life event occur date.