Incorrect Facebook Ad Conversion Data

[Mapro01]

Hello team, 

Recently we have started with Facebook Ads. On Facebook Ads manager, we are able to see the purchases but there is a discrepancy in purchase value. This is affecting overall ROAS. Check the SS. 

Also, in Shopify, the conversion details are absent for some of the conversions. So, we won't be able to track how many conversions we actually received from Facebook on Shopify either. 

UTM tracking is in place but on GA4 purchase values are not reflecting for a campaign. But on Facebook, there are purchases present. 

GA4 Dashboard

Pixel installed by Facebook Sales Channel. We are using GTM and GA4. The domain is verified. We are using Shopify basic plan. So, no manual script can be added on checkout. 

I reached out to Facebook with the same issue. Kindly check their response below. 

I reached out to the Shopify team for correct data reflection on the platform. No concrete resolution came. 

How can I able to see the purchase conversion value on Facebook ads manager and the correct value of conversion on the Shopify platform? 

Hoping to resolve this issue as this is critical to scaling up the advertising and store sales. 

Thanks in advance.