Serial dilution idiot 😂

Honestly I’m so confused right now please (this is for BSA standard curve):

2.0mg/ml of stock solution. I need to make following in 5ml :

40 micrograms/ml 20 micrograms/ml 10 micrograms/ml 5 micrograms/ml 2.5 micrograms/ml 1 micrograms/ml

So correct me if I’m wrong but 1ml of stock in 4.90ml of PBS to get 40. Then 2.5ml of that solution into 2.5ml of PBS (=5ml). Then continue that 2.5ml of solution and 2.5 ml of PBS until the last one. Finally I take 2ml of the 2.5 solution with 3 ml of PBS.

I’m so confused 😕