take up slack under the frame
How much slack you need will depend on your unit, but mine has a bit less slack than the chains (so it won't come close to dragging) and it does fine. It only sags about half as far as the chains. I have a looped bungy cord permantly in place (where the chains connect to the A-frame) to keep the wire from sagging too much.
Rather than cut it, you might be able to take up some of the slack under the belly of your A/S by loosening the clips, pulling it back, widening any turns, and maybe adding one more retaining clip.
When we got ours, it still had an old style plug. I switched to the new style, but lost a few inches. When we switched to the Hensley Arrow hitch, I needed those few inches plus a few more. Fortunately, I was able to pull out some excess that was looped under the frame.
Hey, its the only way to be sure!