It's intentional that the single value has a little bit different sizing, to keep that level more consistent with prior versions. We got a lot of negative feedback about changing it in a meaningful way from people used to the existing thing. So that specific level of detail does look a little different and size a little different than the rest.

Originally posted by jmccaskey:

It's intentional that the single value has a little bit different sizing, to keep that level more consistent with prior versions. We got a lot of negative feedback about changing it in a meaningful way from people used to the existing thing. So that specific level of detail does look a little different and size a little different than the rest.

I understand trying to maintain the previous look, but the issue is that half of the notches on the slider are effectively doubled, but that isn't the case when using other "performance level detail" options, and the mismatch between the two persists until the "text scaling" setting is changed again (or presumably until the overlay is restarted) which I believe is undesired.
For a clearer example: When I use "Text scaling" notch 4, with "single value" I get a size equivalent to notch 3, with any other performance level detail, it is a bigger size, however the smaller size persists when I switch from "single value" to the other options, and vice versa, the bigger size persists when switching from other options to "single value".
While I haven't tested it I suspect it does *not* persist between overlay restarts, and even if it does it just does not make for an intuitive user interface, displaying the raw value alongside the slider may be a more appropriate solution if you maintain the asymmetric text scaling options between different "performance level detail" options, because an abstract slider changing it's behavior based on a separate setting doesn't exactly make sense.