Users cannot use 2 same platforms in a single stream it will be termed as custom RTMP count for 2nd of same platform used. Usage of the limit is counted across all the streams created totally and not per stream.
Example - You have Broadcast x 2 plan where you are eligible to use 2 FB / custom RMTP. (FB - Facebook , YT - YouTube)
If you have added 1 YT + 1 FB and wanted to a add 2nd YT it will termed as custom rtmp count for the 2nd YT account added.
Broadcast Basic - $9.99
Users can stream to FB profile via API (auto live) , but for connecting to Page & Groups they need to connect manually via server + key and hit the go live button at FB page to be live.
Users can stream to FB profile / pages / groups via API (auto live) from Broadcast x 2 and higher plans - $14.99 + plans
Check the pricing here - https://castr.io/#pricing