This is designed so it more or less matches real life. Far more hitters get the bigger money bonuses as IAFA's than pitchers. Most years, the top 30 lists will only feature something like 3-5 pitchers.
http://m.mlb.com/prospects/2019?list=int
http://m.mlb.com/prospects/2018?list=int
http://m.mlb.com/prospects/2017?list=int
The scouting discoveries who autosign with your team are much more of a 50-50 split, again to match rl numbers.