diff --git a/ansi-tests/format-b.lsp b/ansi-tests/format-b.lsp
index 949176039e704353ec26945f135fc45836aabd07..fb116da7e330d1a6aecd9c0b5843902cad0000b8 100644
--- a/ansi-tests/format-b.lsp
+++ b/ansi-tests/format-b.lsp
@@ -401,10 +401,12 @@
 (deftest format.b.21
   (let ((fn (formatter "~:@b")))
     (loop for x in *mini-universe*
-	  for s1 = (format nil "~@:B" x)
-	  for s2 = (let ((*print-base* 2)) (format nil "~A" x))
+	  for s1 = (let ((*print-base* 2)) (format nil "~A" x))
+	  for s2 = (format nil "~@:B" x)
 	  for s3 = (formatter-call-to-string fn x)
-	  unless (or (integerp x) (and (string= s1 s2) (string= s1 s3)))
+	  for s4 = (let ((*print-base* 2)) (format nil "~A" x))
+	  unless (or (integerp x) (and (string= s1 s2) (string= s1 s3))
+		     (string/= s1 s4))
 	  collect (list x s1 s2 s3)))
   nil)
 
diff --git a/ansi-tests/format-d.lsp b/ansi-tests/format-d.lsp
index 0f9655e073d650f750e4e2dc9ec0779b632b50db..8cee9db0cea3554241470dd5c4e7e08e1e91fefd 100644
--- a/ansi-tests/format-d.lsp
+++ b/ansi-tests/format-d.lsp
@@ -438,9 +438,10 @@
 
 (deftest format.d.21
   (loop for x in *mini-universe*
-	for s1 = (format nil "~@:d" x)
-	for s2 = (format nil "~A" x)
-	unless (or (integerp x) (string= s1 s2))
+	for s1 = (format nil "~A" x)
+	for s2 = (format nil "~@:d" x)
+        for s3 = (format nil "~A" x)
+	unless (or (integerp x) (string= s1 s2) (not (string= s1 s3)))
 	collect (list x s1 s2))
   nil)
 
diff --git a/ansi-tests/format-o.lsp b/ansi-tests/format-o.lsp
index 7a98d247835e17316b368ea2ffeb2032f16ec4d5..60176aeb0ebb82adf812717e25188579a5d40113 100644
--- a/ansi-tests/format-o.lsp
+++ b/ansi-tests/format-o.lsp
@@ -404,10 +404,12 @@
 (deftest format.o.21
   (let ((fn (formatter "~:@o")))
     (loop for x in *mini-universe*
-	  for s1 = (format nil "~@:o" x)
-	  for s2 = (let ((*print-base* 8)) (format nil "~A" x))
+	  for s1 = (let ((*print-base* 8)) (format nil "~A" x))
+	  for s2 = (format nil "~@:o" x)
 	  for s3 = (formatter-call-to-string fn x)
-	  unless (or (integerp x) (and (string= s1 s2) (string= s2 s3)))
+	  for s4 = (let ((*print-base* 8)) (format nil "~A" x))
+	  unless (or (integerp x) (and (string= s1 s2) (string= s2 s3))
+		     (string/= s1 s4))
 	  collect (list x s1 s2 s3)))
   nil)
 
diff --git a/ansi-tests/format-x.lsp b/ansi-tests/format-x.lsp
index 83fe5f68b7280757f1ff2b5b2233d7c0c52a9355..2002b2eec64eb89424da9baacff371fc16cef0c2 100644
--- a/ansi-tests/format-x.lsp
+++ b/ansi-tests/format-x.lsp
@@ -407,10 +407,13 @@
 (deftest format.x.21
   (let ((fn (formatter "~:@x")))
     (loop for x in *mini-universe*
-	  for s1 = (format nil "~@:x" x)
-	  for s2 = (let ((*print-base* 16)) (format nil "~A" x))
+	  for s1 = (let ((*print-base* 16)) (format nil "~A" x))
+	  for s2 = (format nil "~@:x" x)
 	  for s3 = (formatter-call-to-string fn x)
-	  unless (or (integerp x) (and (string= s1 s2) (string= s2 s3)))
+	  for s4 = (let ((*print-base* 16)) (format nil "~A" x))
+	  unless (or (string/= s1 s4)
+		     (integerp x)
+		     (and (string= s1 s2) (string= s2 s3)))
 	  collect (list x s1 s2 s3)))
   nil)