I just notice you say there is not delay on start of layout.
So this is the key, there is no need to load every time your score/level/coins change.
Just do it once the player open your game and add a dictionary to hold your variables while the users play your game.
So if a level end and you collect 100 coins, save the coins to your local storage but not load it back,just save it and to a dictionary and continue the game with the dictionary values.
Now, as blackhornet say its better to use a dictionary to have only one save/load. And this is up to you if you want to have a game and run with no issues then you have to change your code and add the dictionary.