First: "Save as."
Then open the pool and check the original tempo of all the files there before changing the tempo.
You might have to use the "View/Attributes" pull down to make tempo visible in the pool.
They should be set to 110 originally, if not change them.
Check the "Musical Mode" in the pool and ensure that it is checked for all files.
Then, with your tracks in Musical mode, it should work.
You could also use Media Bay to set the tempo of the original files.
I don't do this often so maybe someone else can chime in if I'm in error here.
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