Panel Showing "FR120%"... Huh?

Hello All.

I've got a Prusa Mendel with RAMPS 1.4 running Marlin V1.0. It has been working reasonably well for me for a while, and it continues to do so.

Today, I finally got around to attaching the Reprapdiscount Ultipanel/SD card reader, and, running off of it, I'm printing a knob for the thing as I type this. My question is about something it is showing me on the LCD screen: "FR120%"

I assume it is trying to tell me that my feed rate is at 120%. But which feed rate? And why isn't it at 100%? And it might not even mean "feed rate." Just an F and an R in a single cell, then 120%. I can't find any Marlin value I've set to this, nor have I found anything online, other than pictures of other LCDs happily displaying 100% Can someone point me to the place where I can find out what this means, and if and how I might mess with it?

TIA.

And on the second print (the front of a case for the panel) I see FR110%. So now I'm looking in (Slic3r 0.9.10b-generated) gcode files, and I don't see anything in there either. Just thinking out loud for anyone who wants to assist with my de-baffling.

When you turn the dial while its printing it will increase and decrease the speed that its printing at. It should be 100% by default. Are you sure you're not turning the knob after the print has started?

Thanks for the response. It could easily be that I'm turning the dial during the print. I'll explore that possibility.