jet-cone

I have never been able to plot a route in the game with jet cone boost. Every time it gives me an error about the jump exceeding the maximum fuel my FSD can use per jump. I don't even have cargo!

Why when I choose fastest route + jump through neutron-stars (aka jet-cone jump) it makes a route with maximum one jet-cone boost (but for trips longer than 5-6 jumps its like almost zero) and then its just simple star-to-star jumps? For example everyone we know about Spansh Neutron plotter...