"For example: if a RB runs in a TD from 5-yards out, I get 6 points. But if the TD is run in from 10-20 yards away I get 10 points. 

Our table for RUN TD distance scoring goes like this:
0-9 yd TD = 6 points
10-20yd TD =10 points
+21yd TD = 15 points"

You use a distance scoring system. While it is very easy to grade out a player's points after the game, predicting his score before hand is completely different. Keep in mind Leaguesync works with forecast data and not post-game stats. That's a huge difference. 

In order for Leaguesync to perfectly mirror all possible distance scoring systems out there, it would require forecasting the number of TD scores from 1-yd out, 2-yds out, 3-yds out all the way to 100-yds out for every skill position NFL player. In addition, it would require doing this every week during the season and even in the preseason. Frankly, that's just not practical. Far more importantly, it wouldn't be highly accurate and could lead to poor results. 

Nobody can accurately predict how many 42-yd TDs Mahomes will have vs. 43-yds TDs vs. 50-yds TDs etc. At 4for4, we only forecast statistics we feel we can accurately and mathematically forecast.

Still, all is not lost - in fact, far from it!  Leaguesync can address long-distance TD scoring. Here's how. 

First we need to establish an NFL baseline for Passing TDs and Rushing TDs. The charts below do this for us and they are based on years of NFL game data. 

From the chart you can see that 77% of all rushing TDs are 0-9 yard runs. And 10-20 and 21+ yard TD runs occur about the same percent of the time - 10% and 13% respectively. With this knowledge and the fact you get 6-points for a 0-9 yd run, and 10-20 and 21+ TDs occur with about the same frequency, go to Leaguesync and enter 6 and 6.5 as follows: 

6.0 --- Points per Rushing TD
6.5 --- Points Typical Bonus given for Long Distance Rushing TD 

This will very closely mirror your system and will provide you with a robust solution for rushing TD distance points. Likewise, follow the same process for Pass/Rec TDs. 

Using this method will give you a competitive advantage over your rivals and that's the name of the game.