corrected residual larger than 5 ppm

Usually when performing the tuning, in section of TOF mass calibration data of the tune report, the requirement for  the corrected residual is less than 0.5 ppm.

For QTOF 6530,M when performing the system tune in mass range m/z 3200, the corrected residual is less than 0.5 ppm, but when change the mass range back to m/z 1700 and performed the transmission tune, the corrected residual is larger  than 0.5 ppm , how this problem be solved?  

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