I'm a little confused on a few points...

1) If there is a minimum of 50 candidates needed, why have a price per candidate at all? Why not just have a base fee of 50000, then every subsequent participant be applied to a tier?
2) Do the tiers take into account the minimum amount of candidates? That is if there are 80 participants, 50 of which fall into the minimum, does that mean there are 30 that fall into "tier 1" (1000), or does that fall into "tier 3" (600)?

Hope my questions were clear.