I am using Facebook Attribution API to collect attribution data using the Facebook graph API. I am able to make GET requests and get responses from the API but I have some trouble to build my request parameters.
If you are familiar with Facebook, there is a page available at https://business.facebook.com/attribution where you get informations about all of your different sources channels. In my case I have around 10 different sources channels listed bellow:

What I am trying to achieve is to get the net_media_cost for each of those channels. However, the official documentation of the Attribution API does not say anything about this. Maybe it's not possible, but I guess the Attribution API should be able to do it.
If you check the bottom of the documentation, there is a source channel but it's a generic channel type and not accurate enough for what I am looking for (google generic vs google paid for example)

This is the request I am doing when using the source_channel from the documentation. The same from the Conversion Metrics by Attribution Model on the Attribution API documentation:
https://graph.facebook.com/v9.0/?
ids=<BUSINESS_UNIT_ID>
&fields=conversion_events
.filter_by({"ids":["<CONVERSION_EVENT_ID>"]})
.metric_scope({
"filters":{
"click_lookback_window":"2419200",
"view_lookback_window":"86400",
"visit_configuration":"include_paid_organic"
},
"time_period":"last_thirty_days"
})
{id,name,cost_per_1k_impressions,cost_per_click,cost_per_visit,net_media_cost,report_click_through_rate,report_clicks,report_impressions,report_visits,last_touch_convs,last_touch_convs_per_1k_impress,last_touch_convs_per_click,last_touch_convs_per_visit,last_touch_cpa,last_touch_revenue,last_touch_roas,total_conversions,
metrics_breakdown
.dimensions(["source_channel"])
{source_channel,cost_per_1k_impressions,cost_per_click,cost_per_visit,net_media_cost,report_click_through_rate,report_clicks,report_impressions,report_visits,last_touch_convs,last_touch_convs_per_1k_impress,last_touch_convs_per_click,last_touch_convs_per_visit,last_touch_cpa,last_touch_revenue,last_touch_roas}
}
&access_token=<TOKEN>
This is the result:
{
"<business_unit_id>: {
"conversion_events": {
"data": [
{
"id": "<custom_conversion_id>",
"name": "Total Device",
"cost_per_1k_impressions": 298883073.80651,
"cost_per_click": 7611028.5055993,
"cost_per_visit": 2292374.9356985,
"net_media_cost": 10227213000000,
"report_click_through_rate": 0.039269735172667,
"report_clicks": 1343736,
"report_impressions": 34218107,
"report_visits": 4461405,
"last_touch_convs": 16041,
"last_touch_convs_per_1k_impress": 0.46878689110417,
"last_touch_convs_per_click": 0.011937612745361,
"last_touch_convs_per_visit": 0.0035955041068901,
"last_touch_cpa": 637567046.94221,
"last_touch_revenue": 5752967.9242927,
"last_touch_roas": 5.6251570435588e-7,
"total_conversions": 23156,
"metrics_breakdown": {
"data": [
{
"source_channel": 3,
"cost_per_click": 0,
"cost_per_visit": 0,
"net_media_cost": 0,
"report_clicks": 1154015,
"report_impressions": 0,
"report_visits": 1071516,
"last_touch_convs": 10801,
"last_touch_convs_per_click": 0.0093594970602635,
"last_touch_convs_per_visit": 0.010080110796292,
"last_touch_cpa": 0,
"last_touch_revenue": 3243197.5881846
},
{
"source_channel": 1,
"cost_per_visit": 0,
"net_media_cost": 0,
"report_clicks": 0,
"report_impressions": 0,
"report_visits": 920001,
"last_touch_convs": 4434,
"last_touch_convs_per_visit": 0.0048195599787392,
"last_touch_cpa": 0,
"last_touch_revenue": 2165112.2343256
},
{
"source_channel": 2,
"cost_per_1k_impressions": 298883073.80651,
"cost_per_click": 53906594.420228,
"cost_per_visit": 95867239.714663,
"net_media_cost": 10227213000000,
"report_click_through_rate": 0.0055444621761221,
"report_clicks": 189721,
"report_impressions": 34218107,
"report_visits": 106681,
"last_touch_convs": 806,
"last_touch_convs_per_1k_impress": 0.023554780514305,
"last_touch_convs_per_click": 0.0042483436203689,
"last_touch_convs_per_visit": 0.0075552347653284,
"last_touch_cpa": 12688849875.931,
"last_touch_revenue": 344658.10178253,
"last_touch_roas": 3.3700100093988e-8
},
{
"source_channel": 0,
"cost_per_visit": 0,
"net_media_cost": 0,
"report_clicks": 0,
"report_impressions": 0,
"report_visits": 2363207,
"last_touch_convs": 0,
"last_touch_convs_per_visit": 0,
"last_touch_revenue": 0
}
]
}
}
]
},
"id": "318429215527453"
}
}
The result of that request has everything I am looking for expect that the source_channel is the one from the official documentation and I would need to have it spliced based on my own attribution channels.