All Championship teams are guaranteed a minimum 11 home meetings (8 league,1 KO cup,2regional) so if your team doesn't progress in either competitions you're only going to see 11 matches in 6 months which seems bonkers to me.
Think any rider that did not ride for a Championship team after Newcastle folded would automatically go back to their starting average but it's speedway so you never know.
So you're saying Berwick lose more on double headers than a stand alone NDL match I personally find that hard to believe 2 or 3 of the people I stand with do the do the double headers not the stand alone ones myself included as we have round trips in excess of 100 miles.