Just to clarify, by upgrading to 5.5, JPM300 is referring to bringing the vm hardware level up to vmx-10. If the hosts are at 5.5 but the vm is still at 9 or below, the vmware tools upgrade will reboot the vm unless the appropriate suppress switch is used.
VM version 8 (5.0 level)
/S /v"/qn REBOOT=ReallySuppress"
VM Version 9 (5.1 level)
/S /v"/qn REBOOT=R"
VMs at vmx-10 do not require the switch.