Thanks for building this. I had some discrepancies which took a little time to figure out so I'll lay out what I found to see if that helps anyone.
We have more than 1 store and are based in the UK so charge VAT.
Store A has product prices excluding tax and then tax is added on at checkout.
Store B has product prices including tax.
In Data Studio "Item Revenue" will be product prices excluding tax and shipping for store A and including tax for store B. Store B will match the 'sales' report in Shopify because the Shopify Gross Sales figure is excluding tax, but Store A will not.
You can create a 'Total Revenue' figure by creating a calculated field "Item Revenue+Shipping Cost-Total Discounts". You can create a Net Revenue figure by removing Refunds from that. However, as previous posts mention, refunds are based on the order date, not the date the refund is made. Shopify reports on the date the refund is made so the net revenue figure will not match Shopify reports.
Lastly, I'm getting an issue where time series (bar charts, line graphs) are not showing correctly. They're missing loads of data, while scorecard boxes are showing it OK.
Fantastic application. We've been playing around with it and love it. Recently we had this error pop up:
Shopify API Connector requires your Shopify API Connector key or token in order to access your data. Do not enter your Google account information.
I think on your site the key is visible, but it's partially cut off: