But for EDDB to calculate profit per jump it would need to know your ship details such as jump range with proposed cargo onboard fuel capacity presence of a fuel scoop etc then plot your course, that seems to be more the job of a pure trading tool does the Trade Computer Extension or one of the other external tools do that? Profit per Ly would be a lot easier.
Personaly when I want to find places further away than where EDDB shows I change my location system.
Oh my, where are the times where people could do something like this approximately in mind - nothing is required there, like you see 2.3M payout, you would have split it into 2 runs - which means 3 legs - approx. 750k per jump without to use a calculator, doesn't have to be much more precise and requires no other tool than a brain and can be done in a second. So what do you need a tool for here - you have different offers and you just do an approximate math in your mind - quick and easy. Over time you do not even have to do the math anymore, you get a feeling for it and just looking at offers similar to those you had before will help you to make the decision by experience instead of math.
Profit per ly is crap - because it takes you about the same time to do a jump, regardless if that is 8ly or 40ly (because the hyperjump sequence takes as long as is required to load the next system - it's an animated loading screen actually) - and time is money. Ok, one would eventually have to pay attention to how far the destination is from it's sun - something 39ls away is quickly reached, with 390,000ls that takes like 15 minutes.
And just a little pun - if you would really want to know what is better, you would as well have to take opportunity costs for using tools instead to do missions into account as well. But this is daisy cutter economics. For practical purposes a quick and fast approx. math done in mind is the quickest and good enough to make a decision - a better decision which takes eventually longer might be worse, when you take opportunity costs into account - like what could you have earned in that time where you used that tool - these are actual costs, opportunity costs.