The pricing scheme is based on a per-sheet-charge with a maximum threshold and a defined time period. We provide the services to individuals and to institutions.
For institutions we provide them the capability to create as many users as they want under their billing scheme.

For example: assume that for an institution the per-sheet-charge is 0,20 euros with a threshold of 1500 sheets for one year. If the institution has corrected 1000 sheets the charge will be 1000*0,20=200 €. If there were sheets corrected, the charge would be 1500*0,20= 300€ and NOT 2000*0,20.