The enrollment forms with the price structure is here. NSIP enrollment form
In addition to the enrollment fee there is a $2/head data fee for any animal that you turn a post 90-day measurement in on if it has not been marked as a cull or commercial animal. If you read the enrollment form it refers to section 4.14 in the Quality Assurance Manual. In there it tells you that you need to put a CU or a CO in the tag number to indicate the culls and commercial animals. The CO & CU belong in the 11 & 12 digit location. You should not mark more than 30% of your lamb crop this way. This is where Lambplan would want us to have a 10 for this year. It is also where a lot of us US breeders are putting letters to indicate our flocks. CO & CU should not be used for anything besides this cull & commercial reason. This does mean that you would have to do a retag with the CO or CU at the time that you enter a measurement for over 90 days if you already have sent partial data (i.e. birth info) in on them and do not want to be billed for that animal.