My imperial scale was in the manual. And that's where I left it, but secured it with a piece of tape in the event it is ever needed, although I'll likely never use it. I think the markings are not well delineated at 1/4, 1/2, and 3/4, and it would have been nice to have numbers at the major fraction marks, and not jsut at the inch marks.
I decided to stick with metric. It is easy to read. I have as many metric rulers as imperial, and I have a tape measure with both, so it just made sense to me to use metric for setting depth. I do use both measurement systems, and have both metric and imperial Woodpecker rulers I use to set my Seneca Parallel Guides.
I love the TS 55 REQ, but the imperial stick-on scale is pretty marginal, and not what I would have expected from Festool.