Apply Partner Discounts first in the price waterfall with Salesforce CPQ

The Price Waterfall with this feature active modifies the flow of price field calculations to the following order:

List Unit Price -> Partner Unit Price -> Regular Unit Price -> Customer Unit Price -> Net Unit Price

For example, if you have a product priced at $10,000 and a quantity of 100 with a Range Discount Schedule(system discount) of 10% if the quantity is over 10, pricing would flow as follows:
 

List Unit Price: $10,000
 

Partner Discount = 20%
$10,000 * 0.80 = $8,000
Partner Unit Price: $8,000

System Discount = 10%
$8,000 * 0.9 = $7,200
Regular Unit Price: $7,200

Additional Discount = 50%
$7,200 * 0.5 = $3,600
Customer Unit Price: $3,600
 

Distributor Discount = 50%
$3,600 * 0.5 = $1,800
Net Unit Price: $1,800
 

Behavior with Pricing on Renewals
The following is how this feature works with CPQ's available Renewal Pricing Methods.

'Same'
The Distributor Discount does not pull to the renewal quote lines, but the Partner Discount does.
With the above Scenario, "​$3,600" is what pulls over as the Customer Unit Price of the Renewal Quote Line.

'List'
Only system discounts map over to renewal.

'Uplift'
Same behavior of the 'Same' Pricing Method unless an Uplift is applied at the Contract or Subscription level.
If Uplift is defined, the Renewal Quote Line’s Regular Unit Price will be the List Unit Price after System Discounts,

Uplift is applied to the Customer Price of the Subscription to establish the Customer Unit Price on the Renewal Quote Line, and the difference is what is populated in the Additional Discount Amount.

The Distributor Discounts do not pull over to the renewal.

Considerations: 
The Product Option's Discount (%) and Discount (Amt) are not considered for calculations when ApplyPartnerDiscountFirst is enabled on the Quote object. While the Quote Line still uses these Product Option fields to calculate Special Price, however, this field is bypassed while calculating any proration when ApplyPartnerDiscountFirst is in use. In this use case, customers can use a Price Rule Price Action to inject the Product Option's Discount (%) or Discount (Amt) into the Quote Line's Additional Disc. % or Additional Disc. Amt fields. 

NOTES: 

• When using the ApplyPartnerDiscountFirst__c special field, this limits the use of Unit Cost + Markup due to both fields depending on SBQQ__SpecialPrice__c.
• When ApplyPartnerDiscountFirst__c is enabled on a Quote, SBQQ__SpecialPrice__c is prorated.
• When this special field is created, Orders do not automatically pull the correct price from the Quote lines to Order products, in order to have the correct price on the Order products you also need to create the same field named ApplyPartnerDiscountFirst__c on the Order object.