Sales report from REST API order data

[annapurna]

Hi,

We calculate the sales report data by using the order data. processed_at time for order and refund is used to determine if an order belongs to the sales report for a particular day or not. However, there has been some discrepancy lately due to Shopify. Please see the example below:

Orders from our dev store

 3019333992520 

created_at 2020-12-29T09:57:52+02:00

updated_at 2021-01-18T13:42:24+02:00 (added new line item )

processed_at 2020-12-29T09:57:52+02:00

This order appears in the sales report at 2021-01-18 based on the updated_at date and there is no information about what was updated. But the sales report at Shopify contains information about the line item that was added on 2021-01-18. See screenshot below.

Sales report for 2021-01-18 (Shows the report for the added line item for the order 3019333992520 that was processed_at 2020-12-29T09:57:52+02:00 )

2021-01-18

The screenshot below shows the sales report for 2020-12-29 when the order was processed.

In another example, if we update anything other than line-item or refund for example note, then the order's updated_at date is different and we can not rely on the updated_at date to create our sales report.   

Can you tell me how does Shopify decide internally to include an order/ line item order in a sales report for a date?