Plunge at least partially counteracts a conventional lead screw tendency to pull into the back lash, with a little drag on gib clamp; where climb profiling usually refuse cooperation. When unavoidable a 'rougher' aka 'corn cob' withstand climb better.
Haven't tried much plunging steel with one, but it ran aluminum terrific, at 1.5 diameter depth. The GIF could be close to 3x, just intermittent squeaking.
Squeaks are cue that cutting isn't up to snuff, lathe, mill, sawing, even a hand file; have to bump rates to find sweet spot. Could be to increase or reduce. Best justification for variable rate control.