If there are any doctors on this forum, could you please explain the billing cycle you have with the insurance companies.

From what I understand the process should be like this:
1. Doctor provides some treatment
2. He passes his papers to some person, let's call it "coder"
3. That person converts the treatment details to standard codes
4. Let's say we have 837 hipaa transaction, coder either puts these codes on the paper form or "somehow" creates a hipaa data file on his computer with these codes as a part of it.
5. In case of electronic document, it is being sent either to the clearinghouse or to the insurance company directly
6. On the other side the file gets validated and either sent back with the failed acknowledgment or successful acknowledgment is sent back.
7. Then doctor gets paid based on the transaction he sent

my questions are:
1. In case of electronic transaction - is doctor charged by insurance company for each transaction or he can send as many invalid transactions as he wants?
2. What programs are used to create hipaa files, to manage all the forms etc.?
3. Who exactly sends the file - program internally, or somebody has to submit the files manually?