Yes its intentional its meant to be a skill new players can pick up really quick and earn a little bit of cash, in testing i was able to level up to 10 after my first truck load of oranges in about 30 - 45 mins.
This isnt over kill as even at full skill level it still takes you 10 - 15 mins to fill a truck.
It takes alot of fruit pickers and smoothie makers to make alot of cash from this and its all balanced via the Economy as you can only sell the apples and oranges at what people are willing to buy them at.
You have to remember that it takes 8 fruit per smoothie and thats a lot of fruit!
Excellent news! This has now been fixed by the development team and will be released in a future server update.
Thanks for doing your bit to help us keep the servers bug free!