Improve Pricing and Discount Formula

This is Sam from the USA, a new drop shipper. Recently I've started my business and I found some uncomfortable situation with Pricing and Discount formula. Here I'd like to discuss that.
Now AliDropship plugin setting up the pricing and discounts as AliExpress Offers.

Let me explain,
iPad Case Listing Price is showing $20 on AliExpress. After 50% discount, the price is $10 on AliExpress. Now according to pricing formula, when I am importing that product, it shows same discount offer as AliExpress. And a user cannot change or input any other discount amount into the "Discount" box. Yes, a user can change sale price and list price individually. But I think changing the discount amount is much easier than calculating the price and type it into the "List Price" and "Sale Price".
So, my suggestion is, let the user decide how much discount they will offer to their customer. Don't fix some default discount. I think, there have a lot of users who actually not willing to offer any discounts on their website other than coupon offers. So, Make it more simple for them.