As a Super Admin user you have the ability to make certain line items under the Pricing rules as Fixed Quantity and Fixed Pricing. By using these features your team will be unable to change the Quantity or Pricing before sending a contract to a customer.
Fixed Pricing and Quantity Video
To use this feature you will go to Admin -> Pricing Rules -> Choose the appropriate Pricing Rule
By clicking the Fixed Price or Fixed Quantity this will make sure your Team is unable to change the Quantity and Pricing.
Once your team adds the pricing to the contract you will see that those line items are greyed out.