I've been trying to answer this question for months with the help of colleagues and even the Firebase support, but whenever I think I finally found the answer, it doesn't make sense anymore.
I'm trying to track the revenue we are making with our Search Ads. We use Firebase, and I have several events to track this with: in_app_purchase, start_trial + one for each plan and start_subscription. Start_trial is being triggered whenever a user bought a subscription, doesn't matter if he's eligible for a trial or not. If the user is still subscribed after 7 days, the start_subscription event is being triggered.
The in_app_purchase event is tracked automatically, but afaik they track trials with the value of $0 and subscriptions without a trial with the correct $ value. When I sum up the earnings of my start_subscription event, it's less than the iAP revenue. This doesn't make sense, as the iAP revenue doesn't even track the value for users that were eligible for a trial. How do you do this? We're not allowed to have the user id in Firebase without getting a consent, so all data is anonymous. My only way therefore is to fully trust the data I have right there.
Your help is much appreciated, as I think I'm going nuts.