What makes it a little complicated is that #6 & 7 don't actually score, but their places bump other runners back. If we get our top 10 in before the other team's top runner finishes, our #8 & beyond don't effect the scoring. Their #1 would be given 8 points in a dual meet.
The lowest possible score is 15 (1+2+3+4+5=15). In most small races, such as dual or tri meets, all the runners from each team are allowed to run, but only the first five count in the scoring. Larger races usually limit the number of competitors to 7 per team. Our conference meet allows everyone to run, but regionals is just the top 7. The invitationals we run allow the top 7 to run in one race & everyone else in another race.