Unable to replicate analytics report through Graphiql - specifically Gross Sales for lineitem

[dhts]

One of the standard reports within Shopify is "Total Sales by Order" which gives amongst other things for each line item:

Gross Sales - The price of the item excluding VAT and any Discounts

Net Sales - The price of the item excluding VAT but with discounts applied

Taxes - The VAT on the lineitem

Specifically where a discount of 10% has been applied to an order through a voucher code I can get the following through Graphiql:

Original Price including VAT (OriginalTotalSet)

The discount including VAT (AllocatedDiscount)

The VAT paid (Taxlines -> PriceSet)

So I can get Net Sales (The price of the item excluding VAT but with discounts applied) by:

OriginalTotalSet - AllocatedDiscount - Taxlines-PriceSet

But I can't work out how to get Gross Sales for that line item, ie the original price ex vat.

I did try simply dividing by unit price by the VAT rate of 20% but this is giving me rounding errors when compared with shopify as sometimes Shopify will round up and sometimes down depending on how it's treating the VAT on that line. I really need Shopify's view of the ex-tax rate for the lineitem.

It's for accounting purposes so needs to be accurate to the nearest penny.

Any help appreciated.

[tobebuilds]

You might consider asking this on Shopify's developer community forum, since it's an API question:

https://community.shopify.dev/

If you make a post there, please link it here. I'm also interested in hopefully hearing Shopify potentially explain how they decide whether to round prices up or down.