--- a/layout/reftests/writing-mode/tables/reftest-stylo.list
+++ b/layout/reftests/writing-mode/tables/reftest-stylo.list
@@ -66,18 +66,18 @@ asserts(1-2) == vertical-table-specified
 
 # HTTP(../..) == s72-border-spacing-002.xht s72-border-spacing-002.xht
 # HTTP(../..) == s72-border-spacing-003.xht s72-border-spacing-003.xht
 # HTTP(../..) == s72-border-spacing-004.xht s72-border-spacing-004.xht
 # HTTP(../..) == s72-border-spacing-005.xht s72-border-spacing-005.xht
 fails == wm-row-progression-002.xht wm-row-progression-002.xht
 fails == wm-row-progression-003.xht wm-row-progression-003.xht
 fails == wm-row-progression-004.xht wm-row-progression-004.xht
-== wm-row-progression-004.xht wm-row-progression-005.xht
-== wm-row-progression-004.xht wm-row-progression-006.xht
+fails == wm-row-progression-005.xht wm-row-progression-005.xht
+fails == wm-row-progression-006.xht wm-row-progression-006.xht
 fails == wm-row-progression-007.xht wm-row-progression-007.xht
 
 # == table-caption-top-1.html table-caption-top-1.html
 # == table-caption-bottom-1.html table-caption-bottom-1.html
 # == table-caption-left-1.html table-caption-left-1.html
 # == table-caption-right-1.html table-caption-right-1.html
 
 fuzzy-if(stylo,1,7400) == border-collapse-bevels-1a.html border-collapse-bevels-1a.html

--- a/layout/tools/reftest/reftest.jsm
+++ b/layout/tools/reftest/reftest.jsm
@@ -840,16 +840,24 @@ function AddTestItem(aTest, aFilter)
     if (aTest.url2 !== null)
         aTest.identifier = [aTest.prettyPath, aTest.type, aTest.url2.spec];
     else
         aTest.identifier = aTest.prettyPath;
 
     gURLs.push(aTest);
 }
 
+function AddStyloTestPrefs(aSandbox, aTestPrefSettings, aRefPrefSettings)
+{
+    AddPrefSettings("test-", "layout.css.servo.enabled", "true", aSandbox,
+                    aTestPrefSettings, aRefPrefSettings);
+    AddPrefSettings("ref-", "layout.css.servo.enabled", "false", aSandbox,
+                    aTestPrefSettings, aRefPrefSettings);
+}
+
 // Note: If you materially change the reftest manifest parsing,
 // please keep the parser in print-manifest-dirs.py in sync.
 function ReadManifest(aURL, inherited_status, aFilter)
 {
     // Ensure each manifest is only read once. This assumes that manifests that are
     // included with an unusual inherited_status or filters will be read via their
     // include before they are read directly in the case of a duplicate
     if (gManifestsLoaded.hasOwnProperty(aURL.spec)) {
@@ -874,16 +882,20 @@ function ReadManifest(aURL, inherited_st
     inputStream.close();
     var lines = streamBuf.split(/\n|\r|\r\n/);
 
     // Build the sandbox for fails-if(), etc., condition evaluation.
     var sandbox = BuildConditionSandbox(aURL);
     var lineNo = 0;
     var urlprefix = "";
     var defaultTestPrefSettings = [], defaultRefPrefSettings = [];
+    if (gCompareStyloToGecko) {
+        AddStyloTestPrefs(sandbox, defaultTestPrefSettings,
+                          defaultRefPrefSettings);
+    }
     for (var str of lines) {
         ++lineNo;
         if (str.charAt(0) == "#")
             continue; // entire line was a comment
         var i = str.search(/\s+#/);
         if (i >= 0)
             str = str.substring(0, i);
         // strip leading and trailing whitespace
@@ -908,16 +920,20 @@ function ReadManifest(aURL, inherited_st
             while ((item = items.shift())) {
                 if (!(m = item.match(gPrefItemRE))) {
                     throw "Unexpected item in default-preferences list in manifest file " + aURL.spec + " line " + lineNo;
                 }
                 if (!AddPrefSettings(m[1], m[2], m[3], sandbox, defaultTestPrefSettings, defaultRefPrefSettings)) {
                     throw "Error in pref value in manifest file " + aURL.spec + " line " + lineNo;
                 }
             }
+            if (gCompareStyloToGecko) {
+                AddStyloTestPrefs(sandbox, defaultTestPrefSettings,
+                                  defaultRefPrefSettings);
+            }
             continue;
         }
 
         var expected_status = EXPECTED_PASS;
         var allow_silent_fail = false;
         var minAsserts = 0;
         var maxAsserts = 0;
         var needs_focus = false;
@@ -1316,26 +1332,16 @@ function StartCurrentURI(aState)
     gState = aState;
     gCurrentURL = gURLs[0]["url" + aState].spec;
 
     RestoreChangedPreferences();
 
     var prefs = Components.classes["@mozilla.org/preferences-service;1"].
         getService(Components.interfaces.nsIPrefBranch);
 
-    if (gCompareStyloToGecko) {
-        if (gState == 2){
-            logger.info("Disabling Servo-backed style system");
-            prefs.setBoolPref('layout.css.servo.enabled', false);
-        } else {
-            logger.info("Enabling Servo-backed style system");
-            prefs.setBoolPref('layout.css.servo.enabled', true);
-        }
-    }
-
     var prefSettings = gURLs[0]["prefSettings" + aState];
     if (prefSettings.length > 0) {
         var badPref = undefined;
         try {
             prefSettings.forEach(function(ps) {
                 var oldVal;
                 if (ps.type == PREF_BOOLEAN) {
                     try {