Doubt in Table with missing values set

In final table, we get 4 companies which have same profit values ( 2 companies value = a, and 2 companies value = b) in year 2019 as well as 2024, so according to point 4 that at most 2 companies can have same profit...plz explain how to interpret the point....i assumed earlier that only 2 companies can have same profit value not more than