diff --git a/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native.bbappend b/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native.bbappend
index 72d991c..aa8149c 100644
--- a/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native.bbappend
+++ b/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native.bbappend
@@ -1 +1,2 @@
 FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+MRW_EXPRESSION_VARS = "-v PS_DERATING=${POWER_SUPPLY_DERATING_FACTOR}"
diff --git a/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native/mrw-override-settings.yaml b/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native/mrw-override-settings.yaml
index 0bfd515..c823896 100644
--- a/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native/mrw-override-settings.yaml
+++ b/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native/mrw-override-settings.yaml
@@ -5,7 +5,7 @@
               Default: 0
               Validation:
                   Type: "range"
-                  Validator: "MRW_OPEN_POWER_SOFT_MIN_PCAP_WATTS..MRW_OPEN_POWER_N_PLUS_ONE_BULK_POWER_LIMIT_WATTS"
+                  Validator: "[[MRW_OPEN_POWER_SOFT_MIN_PCAP_WATTS/(PS_DERATING/100)]]..[[MRW_OPEN_POWER_N_PLUS_ONE_BULK_POWER_LIMIT_WATTS/(PS_DERATING/100)]]"
                   Unit: "Watts"
           PowerCapEnable:
                Default: 'false'
diff --git a/meta-phosphor/common/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native.bb b/meta-phosphor/common/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native.bb
index 2080a3b..d5ec1bc 100644
--- a/meta-phosphor/common/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native.bb
+++ b/meta-phosphor/common/recipes-phosphor/settings/phosphor-settings-read-settings-mrw-native.bb
@@ -17,6 +17,8 @@
 
 S = "${WORKDIR}"
 
+MRW_EXPRESSION_VARS ?= ""
+
 do_install() {
     DEST=${D}${config_datadir}
     install -D mrw-override-settings.yaml ${DEST}/mrw-override-settings.yaml
@@ -30,5 +32,6 @@
         -i ${mrw_datadir}/${MRW_XML} \
         -s ${DEST}/mrw-override-settings.yaml \
         -o ${SETTINGS}/mrw-settings.override.yaml \
+        ${MRW_EXPRESSION_VARS} \
         -f
 }