I tried to create a form with several formula fields, there are 4 formula fields that calculate based on an input value as below.

Input field 

- Duration

Formula fields

- Production Efficiency

- Machine Cost

- Labour Cost

- Process Cost

When I tried to input and update "Duration", I got a refresh icon, and the form just froze there, and I did not get any result from the formula fields which depends on the input value. I have tried it over and over, it still froze after keying "Duration" value. 

1. What actually does the refresh icon mean?

2. Did I just set up too many formula fields? It seems too heavy for Creator to handle them.