Doug Grainger gives the best information, perhaps he will join this thread.
You should have the new tapered springs installed.
I've been advised not to use WD-40, but to wash the extended jacks with soap and water, and perhaps use a bit of automatic transmission fluid, carefully wiped off.
The right rear jack on my HWH 625 Series occasionally does not fully retract, or takes a very long time. I've actually driven the MH a bit to help it retract, and have resorted to "helping" it with a 2x4 pry bar.
My alarm sounded for 1,100 miles once with the jacks retracted. It was a Friday afternoon, with no RV repair facilities available. I called Coach-Net and they put my in touch with HWH that could not help much, but I did get several calls from them trying to advise me where I could find the fuse to shut the alarm off. They asked me what day the HWH system was installed? I said that I had not idea. . . They said, then it could be anywhere. Good luck. I eventually had to install a new control unit (which I'm not sure that I needed?)