DEX Issue?

[Antonia_Sa]

Hi

I am currently building my own DEX and I have recognized the following case:

1. Visit Pangolin Swap, Pancakeswap or Uniswap. I am using Pangolin for demonstration.

https://app.pangolin.exchange/#/swap

and enter 10 Avax and get following result

2. I am switching the tokens and getting this
   
   

I need to effort over 3 thousand more Pangolin tokens to swap back to Avax. Is that correct and should it not be exchangeable again at the same or current price, e.g. 10 Avax -> 710 Pangolin and 710 Pangolin -> 10 Avax?

I found this issue at Uniswap and Pancakeswap as well but as we know the most DEXs are a fork. Can someone agree or how they calculate the amount?