Yes, Process -> Find/Change is one way to do it, and the one I've used forever and still (mostly) remember how to do.
It's a daunting dialog box but read the help manual on it, you get used to the layout, its a big filter system.
Select the clip you have with the controllers in it, then choose Process->Find/Change from the menu.
Select "None" on the first page to clear everything, then just tick "Control", select 11 as the
number min and max, and for the example above 90 and 127 as the
value min and max
Then press ok, and on the next screen leave the number 11's as is, but change the value min and max to 70 and 110.
Others might have some more modern ways of editing it! Maybe along the lines of when in PRV, display the controller down the bottom, and make sure you have selected the clip. Using the smart tool so it becomes the "move" symbol (arrows), or just the move tool, sliding up and down will adjust all the values with a fixed offset, e.g. -20 to approximate your example above.