I'm using prestashop 1.6.1.0...
The math doesn't quite add up here or am I misunderstanding something?
I have a product for $413.60 - base price.
I put a discount amount of $138.60
So final product should cost $275.00
This is fine for products with no tax rule on them...I've got a tax rule set up for California...8.25%...so when I log in as a customer with a California Address...these are the figures I get on the product page
Original price: $413.60 Special Price: $285.86
With a 8.25% tax I should be getting $297.67 as the final price.
Then on the cart checkout...I'm getting a grand total of $310.16 (free shipping)....where is that extra coming from? And why does the product unit price on the checkout and product page show as $285.86?
It will show all the right prices if you're NOT logged in or if you're logged in with an address that is NOT from California.
The problem is to which customer group the discount is applied. Check if you have another cart rules only for customer, that is not applied for guest. Or check your discount to which group is applied.
Good luck.