the constant effect spring hanger need adjust at site douring cold or instlation stage because of difference of actual load and claculated load. in Chinese code GB10181, the alowable is +-10%, but Mss-SP 58 is +-6% . So for me, it need re-claclualion the system if difference large than those allowance. What is your idea about this issue? what are the percentage in your practice?