Yes, your are correct, shoot-offs will be run with NSSA rules and are miss and out by station.
An example shoot-off scoresheet is available under the iHelp section of the ishoot application.
Things you should know about posting shootoffs: 1. Front Long-Runs will ALWAYS be ODD Numbers unless the shooter dutches a pair or completes the box. 2. Always enter a value in all 3 boxes. IE 24 24 24 for a straight, NS NS NS for No Shows, or 23 0 23 for a shooter missing the VERY Last Target of a box. 3. 1st Long-Runs are the number of targets broken before the first miss by station. 2nd Long-Runs are the number of targets broken between the first miss and the second miss by station. Long-Runs may be but most likely are not the numbers above the targets. 4. If your shooter runs the first box or only misses once. Enter the first box and you will be given a second box. 24 24 24 or 23 0 23 will get a continuation box. 5. If your shooter has a Shoot-Off Long-Run Tie with someone (Example: 1 1 2 ties). A second box will be added and you will be informed they have to continue. 6. Break All Class Ties at your clubs. Keep up with them on continuation lines of the scoresheets. If they get into long continuations because both are missing it will be worked out. 7. See the quick example image below: