We decide in the Tracking Health Check, USD 395. It is read-only: one store, one agreed question (should direct checkout stay on, channel by channel) and up to three systems, usually Shopify admin, GA4 and Merchant Center or one ad platform. You get a written verdict two working days after the kickoff and confirmed access.
A Focused Fix, from USD 450, carries it out, with a fixed quote before it starts. If the task is already clear, I can quote the implementation directly. If we first need to establish the cause or scope, we agree a separate diagnostic engagement.