Exact Extracts from Salesforce Billing Implementation Guide:

“Billing Schedule Groups (BSGs) define how and when recurring charges are billed.”

“The Billing Day of Month field on the BSG controls the regular billing date for the customer.”

“Use the Override Next Billing Date field on the BSG to change the billing date for one cycle only without affecting future billing cycles.”

“Inline editing of BSG fields by users with appropriate permissions allows rapid adjustments to billing schedules without amending or recreating assets.”

Step-by-Step Reasoning:

Requirement:

Regular billing date change: from 15th → 20th each month.

One-time exception for April: bill on April 22 only.

Solution:

Edit Billing Schedule Group (BSG):

Set Billing Day of Month = 20 for future cycles.

Set Override Next Billing Date = April 22 for one-time adjustment.

These changes are performed inline without creating a new asset or amendment.

Why A is correct:Meets both permanent and one-time date changes using existing fields in BSG.

Why B and C are incorrect:

B: Unnecessary amendment—no product or contract change required.

C: “Period Boundary Day” is not used for recurring billing adjustments; it affects order period segmentation, not BSG behavior.

References :

Salesforce Billing Implementation Guide — Billing Schedule Groups and Override Billing Dates

Salesforce Subscription Management Implementation Guide — Billing Frequency and Date Adjustments