Sorting different values from different columns

For a study, I need to calculate the different returns of several IPOs and different application strategies. The companies are ranged in columns, in every column there is the different shares they applied for and the return that follows. However, I need to calculate the averages of every possible amount of shares applied for. Because of the different amount of shares every company offers, it can not be calculated directly, but using the IF function. I have tried this, but in my way it did not worked.

See attachment:
SHEET: Data IPOs
B73 - CJ172: number of shares applied for
B724 - CJ784: the returns for the shares applied for

thanks in advance!!