Mr. Rechard:
Thanks for your timely reply very much. You r right ,the concerned case is Alt-Sustain case. A few of spring hangers (including constant and variable types both) are employed in the system being analyzed.
Removal of the rest on support will surely cause load redistribution throughout the system to some extent, but I think it should not result in qualification checking differntly so much. Spring hangers data change is small between two support setting.
I have emalied model file to you, you may check it for more detals.

Regards

Gino