This is usually caused by one simple setting. If you add more subscribers to Optimize but your price per month/year stays the same, navigate to the 'Subscriptions' tab in 'Optimize'.
Click the 3 dots at the end of the subscription that isn't reflecting the correct price, and click 'Edit Contract Details'
Change 'Per Company' to 'Per Seat/License' and the cost is now related to the number of subscriptions.
