Jet JSG-6DC Combo Sander Belt Tension Adjust?

I recently purchased the above referenced sander. It is the 1 1/2HP model with 6" x 48" belt and 12" disk.

At the time of purchase I noticed the edge of the table closest to the belt (in the vertical position) was not parallel with the belt. The center of the table was slightly worn. I didn't think much about it until I got the unit home and installed one of my 320 grit belts. The belt buckles out in the middle. The picture below illustrates the problem. This obviously effects the quality and accuracy of the sanding.

I called Klingspor (where I got the belt) and they said it was probably the belt and immediately offered to send a new belt at no charge. I tried another belt and the same thing happened...therefore, I don't think it is the belt(s). Particulary since the table is slightly worn in the center where a "buckling belt" has touched the table in past.

I called WMH technical support and they really were not much help in terms of suggesting a fix. However, while talking with the gentleman, we looked a the parts diagram and noticed there is a spring that creates the tension in the belt. There is no obvious adjustment for the spring other than taking the tension adjust assembly apart.

My gut feeling is that the spring may be wound one or two turns too tight. Also, the lever that releaves the tension while changing belts requires significant force to move the roller enough to remove/install belts.

Has anyone experienced similar behavior on their Jet sander? Has anyone tried to adjust the belt tension by taking the assembly apart?