Re: Ana Konjuh
Seems you're right, Donna used 4, for a total of 16 and after I checked the rules again it looks like 4 is the maximum a player can use between birthdays, regardless of where they originate from (junior rankings/junior slam finals/pro ranking). That seems to be the only logical explanation. And if you think of it, it makes sense. Otherwise top juniors would play 20 or more tournaments a year and the whole age eligability rule wouldn't be of much use to prevent burnout.