I think it's because as they've been starting to allude to since Battle of Gods, Shenron has a bias. In BoG, Shenron left as soon as possible and granted no other wishes because of Beerus. In RoF, Shenron outright made Frieza appear in pieces, when he's perfectly reconstituted people from far, FAR worse with no issue. In Superhero, Shenron calls Piccolo "Piccolo-Sama/Lord Piccolo" and gives him "a bit extra." In the DBS Anime Filler, Shenron stayed present all day to grant their Wish even when he could've left at any time. In DBS: Broly, Shenron left at ONE wish to save Broly, when he should've stayed to grant more Frieza Force wishes. We've seen quite clearly now that whilst Shenron has no Monkey's Paw, per se, he DOES reserve the right to **** you over or give extra if he wants. He just CHOOSES not to.