Hey there Marc,
Great question! And I apologize in advance for my long-winded answer.
If you’ve created a single source number for a Facebook ad, and are using the number in both the ads themselves in addition to swapping on a landing page, you are correct: CallRail will always attribute these calls to Facebook and you will not be able to distinguish whether the call was made on Facebook or via the landing page.
That being said, these calls will not be double-counted: we can only send calls to the Unbounce platform as conversions if you’re using keyword-level tracking (more on that here). So all of these calls will be attributed to the source of that single number in CallRail, none will be reported in Unbounce or attributed to the landing page specifically. If you’re using the Facebook integration we’ll send these calls to Facebook, who will then attribute them to the proper ad set inside of Facebook Ads. Facebook can do this because they are aware which Facebook users saw what ads, and will match the CallRail calls to ad sets based on user phone numbers.
If you’d like to distinguish between calls from the ad on Facebook and click-throughs to the Unbounce landing page that turn into calls, I would recommend creating a single number to use in the Facebook Ads and then a keyword pool set to swap either specifically for your ad’s UTM parameters or all sources. You’re correct in that there will be inconsistency on which numbers customers see, but in our experience, the amount of customers confused by this is very minimal and shouldn’t have a huge impact on your conversions.
What will happen in this second scenario:
All of the calls will be captured by CallRail and you will be able to report which calls came from the ad directly vs. click-throughs on the landing page.
Call conversions from the landing page will be sent to and counted in Unbounce.
All of the calls will be sent to Facebook and marked as conversions on that ad if the user’s phone number is on their profile whether from the ad or the landing page.
You will see a discrepancy between Unbounce and Facebook, and this may be considered “double-counted” depending on how you do your reporting. Ultimately, CallRail will be your main source of truth from where the calls are coming from if you want to deep dive, but you’ll be able to see at a high level whether or not the ads are generating calls in both Unbounce and in Facebook.
I hope this helps! Let me know if you have any other questions.