The shipping that you have in these charts has many different values. You will need to create a single rule for each of the possible combinations represented in these shipping tables. This would require quite a bit of effort to incorporate into eCart, but it should definitely be possible. The best thing that I can think of for you would be make use of the FedEx and UPS shipping quote server behaviors to have them calculate the shipping based on the values returned from the api. If you would like to charge any additional amount for the shipping you can set a base rate and a per item increment rate within the server behaviors themselves. I would highly recommend doing it this way as it will be much easier to implement, and should not require you to update on a regulare basis since the values come form UPS and FedEx directly.
As for the quantity discount this too can be very time consuming to make all of these calculations or discounts for this. Calculations work with the columns in the cart and now with recordsets directly, discounts do not work with recordsets at all. If you visit the eCart support page and click on the link on the right side for 'archived documentation' you will find a section with this heading:
You should check out the documents here to get a better idea of how to go about setting up the quantity based pricing.