Article 3 shall not apply where the vertical agreement, directly or indirectly, in isolation or in combination with other factors under the control of the parties has the object or effect of restricting the buyer’s ability to determine its sale price, without prejudice to the possibility of the supplier imposing a maximum sale price or recommending a sale price, provided that these do not amount to a fixed or minimum sale price as a result of pressure from, or incentives offered by, any of the parties.