I'm not certain, but I think springs are designed with some sag in them.
When I lifted my Jeep Wrangler with a set of 2.5" coil springs a few years back, they sagged nearly 1" from the freshly lifted height within about 2 months. When I called the manufacturer to inquire about this, the first thing they asked is how much higher the Jeep was sitting from it's factory stock springs that I replaced. When I said, 2.5" the guy on the other end of the phone said, "Do you have any other questions?"
Anyway, have you given either of these springs a chance to settle in?