Price-related fields

The price-related fields are explained using the following scenario.

Substituting ordered item with a different item

Let's say a customer, Alice, placed an order for 3 pcs of Apples.
And 1 pc of Apple costs £5.18 and has a discount of 20%.
So, the subtotal is £15.54, discount offered is £3.12.
And other fees are tabled below.

Component	Price
Subtotal	15.54
Service fee	1.55
Delivery fee	0.49
Rider tip	1.00
Total	18.58
Discount	3.12
Customer pays	15.46

And the picker, after receiving the order, substitutes 3 pcs Apples with 3 pcs Oranges.
And each Oranges costs £3.00 (notice that discount does not apply in case of substitutions).
So, the components change to–

Component	Price
Subtotal after substitutions	9.00
Service fee	1.55
Delivery fee	0.49
Rider tip	1.00
Total after substitutions	12.04
Discount	0.00
Customer already paid	15.46
Customer gets a refund of	3.42

Reducing the quantity of an ordered item

Let's say a customer, Bob, placed an order of 2 pcs of Bananas.
And 1 pc of Banana costs £3.50 and has a discount of 20%.
So, the subtotal is £7.00, discount offered is £1.40.
And other fees are tabled below.

Component	Price
Subtotal	7.00
Small order fee	2.00
Service fee	0.99
Delivery fee	0.49
Rider tip	0.00
Total	10.48
Discount	1.40
Customer pays	9.08

And the picker, after receiving the order, removed 1 pc Banana.
Since each Banana gets 20% discount, discount offered is £0.70.
So, the components change to–

Component	Price
Subtotal after amendment	3.50
Small order fee	2.00
Service fee	0.99
Delivery fee	0.49
Rider tip	0.00
Total after amendment	6.98
Discount	0.70
Customer already paid	9.08
Customer gets a refund of	2.80

Component and its JSON field name

Component	JSON field
Subtotal	`subtotal_price`
Total	`total_price`
Subtotal after substitutions/amendment	`subtotal_after_substitutions`
Total after substitutions/amendment	`total_after_substitutions`