Setting SCAN to 0 will not remove the point from your license count. You can view the total number of data streams being used and the total number allowed in PI SMT > Operation > Licensing > General | Data Streams Allowed & Data Streams Used. We have the KB 3157OSI8 with more information on licenses.
Please let me know if you have any questions about this. I am also happy to look up your Account Manager if you are interested in increasing the Point Count on your system.
Now it is clear for me.