Over the winter, I had a spring shop re-arch my springs to bring the rear up by 1 and 1/2". They are 4 leafs. I installed new U bolts and spring pads. I did the final tightening of the shackle bolts with the car on the ground. Springs look like new. Has HD gas shocks. Car now rides very stiff. Is it normal for the spring rate to change when they are re-arched? The spring shop said there would be very little change, but this is a drastic change. Has anyone experienced this? Thanks.