DownlineCount is how many orgs sit exactly this many hops below the caller. It is 0 in the schedule quoted to a caller that has not applied, which has no downline to count.
Level is the upline distance from the org whose spend is being shared: 1 is the direct referrer, 2 and 3 the referrers above it. Nothing accrues past 3.
RateBps is the commission paid at this level, in basis points OF Hanzo's margin (2000 = 20% of margin, never of the customer's bill). Level 1 is the affiliate's own negotiated rate; 2 and 3 are platform switches read live, so this is the schedule actually in force, not one compiled in.