What is the difference between Discount price and Product price campaign?
Discount price and Product price campaign have a distinct difference. Discount price is set under Products (PIM) > Products and immediately puts the product on sale, often marked with a red price.

As for a Product price campaign is set under * Products (PIM) > Campaigns.*A Product price campaign allows you to schedule a campaign and make multi-selection of products to be included in the campaign. You can choose a percentage on the regular price or the already discounted price on products.

What is an exclusive campaign?
Customer or customer group exclusives allow you to create promo codes and cart-based campaigns targeted specifically at certain groups of customers or individual customers.
Why is a product's discount greater than what is set in the Max discount field on the product?
Warning and the option of removal on products that doesn't meet the discount percentage criteria can easily be done.