This has to be operator error unless your host changed something.
The files you indicate should be removed by the upgrade script not added..
When I see:
The following files are reporting a wrong version number
(Make sure you updated these files)All Files Report Proper Version Number
That tells me you missed some files on the upgrade.
You can also keep hitng the retry/refresh button several times and see if it finally catches up to your current status.. It happens sometimes.
I would start from scratch re-upload all the files per the documents and try again.
You may need to go back to 7.5.5 ftp the files over then ftp the 7.6.1 files then run the upgrade script.
Also try the test script at ubbdev Gizmo mentioned to see if there are issues on server requirements.
Another note since you are upgrading from 7.5.5
When upgrading past 7.5.7 you should upload the styles/admin.css and styles/common.css files individually
It is in the upgrade documents.
This may be the whole issue if you skipped this step.