diff --git a/cameo/fped2d2z.pl b/cameo/fped2d2z.pl
index 6e45f29..932f8e3 100755
--- a/cameo/fped2d2z.pl
+++ b/cameo/fped2d2z.pl
@@ -74,7 +74,8 @@ for $z (keys %z) {
 	undef $t;
 	for $s (split(/\n/, $z{$z})) {
 		if ($s =~ /^(-?[0-9]*\.[0-9]*)\s+(-?[0-9]*\.[0-9]*)/) {
-			$s = (($xmax+$xmin)/2-$1)." $2" if $flip_y;
+			$s = sprintf("%.6f", ($xmax+$xmin)/2-$1)." $2"
+			    if $flip_y;
 
 			# re-scan, so that we can flip on both axes
 			die unless $s =~