Thanks for getting back to us in the Community, @Upset User.

I tried this on my test account and I was able to see the amount when I added the sub-customer (project) in the profit and loss by customer report in QuickBooks Online (QBO) Advanced version.

Here are some sample screenshots.

So that I'm on the same page, can you please send us a screenshot of the report? This will help me make sure that I can provide the best resolution for your concern.

I'm looking forward to hearing from you soon.