I am currently on this mission: 

![Mission](https://i.stack.imgur.com/YfS6rm.png)

Does this mean that I have to stock 5 levels at the same time? 

I have received a fully stocked bonus with only two workers before... Does this count towards this mission? ( I assume not)....

*I only ask as I have been stuck on this mission for some time now (and it does not show any progress)*