Hi,
You should not change the limit as this is as per legality. For detail on how chapter VI calcualtion kindly refer the WIKI document which will explain in detail
http://wiki.scn.sap.com/wiki/display/ERPHCM/chapter+VI+-+section+80
http://wiki.scn.sap.com/wiki/x/KokdGQ
With Regards,
S.Karthik