Currently the reports are rendered by a separate engine than the trend view.
At this point, you are going to need to do a manual workaround.
Let DPA choose the top 15 sql hashes and copy off the hash values in the report.
Once you have the top 15, you can then edit the report definition to be user defined and paste back in any sql hash value you want (so remove the excluded one from trends).
I think it's a great idea though to have the option to honor the excluded from the trend view. Feature request?
Thanks for the idea. I'll have to give that a try.