Graphical indicators in PWA

[broot]

I’ve been asked to add the following graphical indicators to show in PWA.

Task Level Status
Red = If you miss a task finish date for a critical path task
Yellow = If you miss a task finish date
Green = Task is still active
Done = check mark

The indicators are as followed:
1 = check mark
2 = Red
3 = Yellow
4 = Green

So far, I have the following code inputted into the Enterprise Fields > Task

Type (number) > Task Status >formula field:

Switch([% Work Complete]=100,1,Date()>[Project Finish],3,[% Work
Complete]<100,4)

My question is twofold:

1. What piece of code I need to add to get the Red to show for overdue
critical path task
2. Is the Date()>[Project Finish],3 the correct code to use?