Thank you for submitting a feature request, Hector
The final price in PrestaShop is calculated from the Base Price and is multiplied by taxes, which means that it is generated dynamically. So if you have a price of $100 and add 10%, the final price will be $110. In order to show it in the grid, we will need to calculate it on the go. Also when you display a thousand products at a time, it should be calculated a thousand times before showing the grid. If you are using a direct connection, that means that we need to wait while the database gives us all prices, calculates them by a tax assigned to the specific product, and after that shows the prices in the column. It will take much time and the application will most likely freeze each time showing products. Also when calculating it backward, you have even more trouble, as it is not as simple as deducting 10%. As you know 110 - 10% = 99. So when you specify 110 as the final price, the calculations would be much more complicated and approximate rather than just deducting specific fixed costs. So it is a much more complicated task to calculate it in the Products Grid. We have implemented such calculations in Mass product changer, you can find an option to apply changes to the final price. While it might be a nice feature, it takes some time to make calculations and you will see a progress bar showing the time for the changes to be applied. When talking about prices in the product grid, it should be calculated each time, as the value is not saved in the database, but is calculated on the fly each time it is shown.
Considering that this feature will slow down the browsing process and might be not as accurate as customers would expect, this feature is considered as complicated. We are open to discussion on how you can see this feature to be implemented (technically). Also, we welcome other users to join the discussion and offer any possible solutions.
At the moment in order to calculate the final prices in bulk you can use Mass Product Changer, Import/export, or use SQL for the update.