I'm on level 844 and there's about 5 or so level Booster mice that don't have all 135 stars in order to have the third tier boosters.
Even the last booster "Traditional Betty" has all 135 stars, giving me access to the third tier booster.
Most of the levels I've played out of 844 levels total, I've won with 3 stars.
I'm not sure why the rest of my booster mice are not at the tier booster Traditional Betty and a few others are.
All of my Booster mice should be able to allow me access to their third tier booster.
Thank you for any help with this.