ACWP vs Actual cost

Hello,

What exactly is the difference between Actual cost and ACWP?

From what I understood, ACWP does not include the cost of a cost resource. IS that correct?

To validate my idea, I created a project with a single task T1 and a single cost resource C1 as follows.

My question : Why is ACWP 250 for task T1? I thought it should be 0.

Please advise.

Thanks & regards

Lakshmi