Total price on the product page before "Add To Cart" button, why not?

I'm having a hard discussion about adding total price per product in product page before adding to cart or not.

The situation:

Our user normally add more than 1 product to cart and our products have a cheap price, but the user never buys just 1. For example, if he is buying a roof tile, he will add 500 tiles. And considering it I thinking the total price could be a benefit helping users to know the individual total (subtotal for each product) before add to cart reducing the shopping cart abandonment. And the experience could improve because this new feature will reduce the number of page changes and we will be very transparent with the user without bad surprises.

As this feature is no common on other e-commerce is being very difficult to approve an A/B test. Adding the total price for each product on the product page looks a good idea? Why not?

I already read this topic but they are talking something more advanced and my user is not adding a shirt or simple items to the cart. I just want to calculate: Product Price X Quantity and show the total price.

See an example of how I expect to do it.