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Depending on the background of public discussions about sustainability and climate change，as well as under the consideration of network operator’s energy costs，growing attention has been paid to the energy consumption of telecommunication (TC) networks in the recent past. In particular，it is important to reduce the power consumption of the access network because of typical consuming of large parts of the power of the entire network due to the sheer volume of the equipment. It is anticipated that the next-generation PON (NG-PON) with a much greater bandwidth，a high customer fan out，long reach，and flexibility in resource allocation - is a natural path forward. Hybrid time-division and wavelength division multiplexing (TWDM) PON is an actively considered NG-PON solution. All the wavelengths are working 24x7 online even though there are a few ONUs or none of ONUs working at these wavelengths. So，The ONU migration mechanism proposed to save the power consumption for the developing NG-PON standard by rearranging the working ONUs at the OLT side to a minimum number of wavelengths and turn off the rest. In TWDM PONs with migration，the time for closing the working wavelength，consists of three time stages:one-trip time from OLT to ONUs to transfer the migration command messages，delay time at the ONU side，and one-trip time from ONUs to OLT to transfer migration Acknowledge messages. With the number of time stages being reduced to one，and in particular，by removing the migration delay，the wavelength closing time can be significantly reduced. We show through simulation that the time required to close a wavelengths in the migration process can be reduced to 1％，under typical ONU online profiles. We investigate how the time of closing the working wavelength is affected by the ONU distance distribution，and what the effect of that on the SLA. Also we aim to reduce the time of wavelength closing in TWDM Multi-PONs by taking into account the ONU distance distribution. We calculate the average time to close the working wavelength with different average distance. Also we discuss the effect of reducing the time of closing the working wavelength in TWDM Multi-PON on the SLA. Our simulation results show that the time saving of closing the working wavelength is more than 99% with exponential ONU distance distribution and more than 98% with uniform distribution.