Thank you for your reply. The command works but it does not check if it levelled.
But it shows 180/90 with the exp bar going out of its gauge. Without levelling up. My call is: $gameParty.changeCraftExperience("alchemy", 90) and I used it twice.
I do have a level up system for all my gathering jobs using a simple check on level, exp and next exp variables. In there I don't use $gameParty.getCraftLevel(cat) but it is working. What I use to store the level and exp into my variables is:
$gameParty._craftLevels.alchemy;
$gameParty._getCraftExperience.alchemy;
(I could not send a picture for some reason)
Edit: Btw! I had to download the core now which is new to me. But I use yanfly plugins. What order do you recommend your core plugin to be?