Hi @ShopifyDevSup , thanks for your explain,
One more quickly question, when merchant change plan (upgrade or downgrade), the billingOn will day billingOn of old plan? Is it right?
Example: if merchant used 10 day with 10$ plan (billingOn: January 1) then they upgrade to 20$ plan, now the field billingOn of new plan is still January 1, it not 30 days after new plan. is it right?
Please confirm it. Thanks in advance!