diff --git a/mpicbg/src/main/java/mpicbg/models/TileConfiguration.java b/mpicbg/src/main/java/mpicbg/models/TileConfiguration.java
index eb01983..bf8b186 100644
--- a/mpicbg/src/main/java/mpicbg/models/TileConfiguration.java
+++ b/mpicbg/src/main/java/mpicbg/models/TileConfiguration.java
@@ -29,7 +29,6 @@
 import java.util.ListIterator;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
-import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Future;
 import java.util.concurrent.ThreadPoolExecutor;
 
@@ -341,7 +340,7 @@ public void optimizeSilentlyConcurrent(
 			final double maxAllowedError,
 			final int maxIterations,
 			final int maxPlateauwidth,
-			final double damp ) throws NotEnoughDataPointsException, IllDefinedDataPointsException, InterruptedException, ExecutionException
+			final double damp ) throws InterruptedException, ExecutionException
 	{
 		TileUtil.optimizeConcurrently(observer, maxAllowedError, maxIterations, maxPlateauwidth, damp,
 				this, tiles, fixedTiles, Runtime.getRuntime().availableProcessors());
diff --git a/mpicbg/src/main/java/mpicbg/models/TileUtil.java b/mpicbg/src/main/java/mpicbg/models/TileUtil.java
index e6f5ff6..103f77a 100644
--- a/mpicbg/src/main/java/mpicbg/models/TileUtil.java
+++ b/mpicbg/src/main/java/mpicbg/models/TileUtil.java
@@ -211,7 +211,7 @@ static public void optimizeConcurrently(
 					int d = maxPlateauwidth;
 					while (!proceed && d >= 1) {
 						try {
-							proceed |= Math.abs(observer.getWideSlope(d)) > 0.0001;
+							proceed = Math.abs(observer.getWideSlope(d)) > 0.0001;
 						} catch (final Exception e) {
 							e.printStackTrace();
 						}