Prestashop Length Width Price Calculator (on The Fly)

Prestashop module.

I need to provide a product of customizable size (height and width) and the price of which is calculated according to a following formula:

price = height + width + others attributes (pre defined like color, capacity etc)

The calculate of price is very simple because usually my products are setting on range of 20 and 20cm, and the minor measure is 60 cm and major is 300cm both height and width.

For example. A customer can set a product with the measures 65cm width and 99cm height and the price will be the same for a product set as 60cm width and 100cm height.

Basically, the rule for rounding is round to a number near into the scale, but a option to configure how will be the rounding rule for each product would be awesome, if this solution doesn't raises problem (+$)

One good solution would be create attributes the same way that prestashop works.
In the combinations, after choosing the group attribute (height or width) and attribute (100cm e.g) setup the range for each value (e.g for 100 cm the range would be 100 to 119cm).

if a value entered by the customer is outside the possible range for the product, front office must inform "product only sold with the measures x (width) and y (height), where X and Y minimum and maximum values ​​of the attributes registered for the respective product.

Finally, all the custom informations (height and width) must be caught and recorded in database.

Ideally, the price would have to be automatically calculated and the customer should be able to add the product to the basket. But a button "Update price " is possible if the first solution raises problem.