Yes, the article David linked was helpful.
Basically, if I get a .pdf that's 1/4" scale and import it into a layout, any measurements I do with any tool matches with what is written on the page. So if a wall is already noted at 10' and I use the tape measure tool, I also get 10'. The led me to believe (possibly incorrectly) that the tape measure tool is set to measure on 1/4" scale. And when I get a .pdf that's in a different scale, the tape measure tool does not line up with what's written.
So when I'm laying out locations of recessed lights, for example, I need the scale measurement to match so that the electrician installs them in the correct places. If I'm laying out based on 1/4" and the electrician is using 3/16", I'll have an angry customer.
The issue with the article is that it seems like a tedious fix, I have to trace over everything. I was hoping that if the tape measure tool seemingly is set for 1/4" scale, it would be easy to change that 3/16" scale.
I did get a suggestion from a friend to create a CAD box to match the known size over the room I'm working on, then resize the .pdf to match the box. That actually worked out pretty well. It might be off by a foot, but on a 40' room it's close enough. It's quicker than tracing over but slower than what I hope would be a couple of clicks to change the measurements to deal with a different scale.
Thanks again for your help.