Can we use Rates-base Salary Components and Grade Rates with a Range?

Client has the requirement to record these salary components:

Base Salary

Superannuation/Pension

Total A = Base Salary + Superannuation/Pension

Short Term Incentive

Total B = Total A + Short Term Incentive

** Grade Rates (Ranges) are set at Total A, which is the sum of Base and Super/Pension.

Following worked example:

Base Salary: $71,748.75

Superannuation/Pension: $8,251.25

Total A: $80,000

Short Term Incentive: 5% of Total A = $4,000

Total B: $84,000

Salary Range: Min: $75,000 Mid: $85,000 Max: $95,000

Range is to be compared to Total A.

Compa Ratio = Total A / Midpoint: $80,000 / $85,000 = 94.12

My questions are:

Do range grade rates work with salary components?

Can we specify which component the rate is applied to? In this case, Total A