FF to extract maximum grade rate from another grade rate

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Hello Experts,

I need to create a fast formula to get the maximum and minimum grade rate value from another grade rate.

For example:

grade rate 'Level 1 - class A': min 10 000, max 20 000

grade rate 'Level 1 - class B': min 20 001, max 30 000

grade rate 'Level 1 - class C': min 30 001, max 40 000

My employee is Level 1 - class A. I know that I can use PER_ASG_GRADE_RATE_VALUE_MINIMUM and PER_ASG_GRADE_RATE_VALUE_MAXIMUM to get values for my employee (10 000 and 20 000). However, what I need is to get maximum values of his level, so 30 001 and 40 000.

Could you please adivse how can I achieve this? Should I found interesting grade manually and change some contexts or is there another DBI that already stores all interesting values?