Customizing Prestashop

I would like to customize my Prestashop website. We do furniture business. And furniture is big in volume for shipping, and needs a special shipping method and pricing. Some of my carriers calculate shipping price just by volume, some of them just by weight, and some of them with both volume and weight. If by both volume and weight, they calculate by weight, and then also calculate by volume, and they compare both results then use the value which is greater, or sometimes which is smaller, or sometimes they sum up two results (volume price+ weight price). For example, my product is 100kg and 1m3. Carrier rates are: Weight rate: 0kg - 50kg —> 3$/kg 50kg -100kg -> 2$/kg Volume rate: 0m3 - 0.5m3 -> 200$/m3 0.5m3 - 1m3 -> 195$/m3 So, 100kg * 2$/kg= 200$ and 1m3 * 195$/m3= 195$ We should use 200$ for the shipping price if the carriers pricing method is to use greater price. Or maybe we should use 195$ if the carrier’s pricing method is to use less price. Or maybe we should use 200$+195$=395$ if the carrier’s pricing method is to sum up two results. So for my product I have to insert both weight and volume. Now there is ability to insert weight of the product in prestashop, also ability to insert height, width and length of the package. But some of my products have more complex shape, H x L x W are not always available. So here we need a field either insert H x L x W or directly insert the volume of the package. Default prestashop shipment method doesn't have option for setting price by volume. And there is no option for setting price per unit. By default prestashop is like this: from 1kg to 5kg—————15$ (price is fixed among this weight range) But I need like this: from 1kg to 5kg—————3$/kg (price is per kilogram among this weight) from 1m3 to 3m3—————300$/m3 (price is per m3 among this volume) from 1m3 to 3m3—————500$ (price is fixed among this volume range) from 1kg to 5kg—————15$ (price is fixed among this weight range) And i need settings for how to deal with these prices. Like, either choose: -volume price -weight price -sum up both volume price and weight price -price which is greater -price which is smaller I need these settings for every routes. For example from point A to point B. And from point B to C. From point A to C and etc. Ability to add prices of two or more routes. For example: Route from A to B. Route from B to C. So if the buyer wants to ship to C, then the system should add prices of routes A to B and B to C. This is two routes only. But I want ability to use to add up unlimited number of routes. Ability to import the shipping price by table.