That doesn't account for the new shares being (presumably) preferred while the purchased stock are common stock.
Common vs preferred stock only matters in the event of same or liquidation if a company - preferred is paid out first. At IPO, both kinds of shares convert into the same public class of stock (with the rare exception of founders creating a special class of shares for increased voting power).
Functionally dilution should be considered in the full context of the financial outcome unless we are talking about voting rights and I wasn’t. For small shareholders the only real value of stock is money. If it is worth less money then its value has been diluted.