TEC provides media space.
TEC has media assets which are resold to the advertiser.
You pay your agency after the distribution or publication.
TEC pays back the "cash back" or "savings".
TEC pays the savings back to the agency or pays the cash back to the advertiser.
Either you keep the cash back by way of optimisation, or, thanks to the savings, you finance services (special campaigns, agency services, surveys, promotions...) or additional media space.
Thanks to the savings, the agency provides the advertiser with a financing solution for surveys, special campaigns, data, dashboard… or offers additional media space.