diff --git a/source/EngineInterface/SimulationParametersEditService.cpp b/source/EngineInterface/SimulationParametersEditService.cpp
index 40111292a..446db6ad3 100644
--- a/source/EngineInterface/SimulationParametersEditService.cpp
+++ b/source/EngineInterface/SimulationParametersEditService.cpp
@@ -28,12 +28,12 @@ auto SimulationParametersEditService::getRadiationStrengths(SimulationParameters
     return result;
 }
 
-void SimulationParametersEditService::applyRadiationStrengths(SimulationParameters& parameters, RadiationStrengths const& ratios)
+void SimulationParametersEditService::applyRadiationStrengthValues(SimulationParameters& parameters, RadiationStrengths const& strengths)
 {
-    CHECK(parameters.numRadiationSources + 1 == ratios.values.size());
+    CHECK(parameters.numRadiationSources + 1 == strengths.values.size());
 
     for (int i = 0; i < parameters.numRadiationSources; ++i) {
-        parameters.radiationSources[i].strengthRatio = ratios.values.at(i + 1);
+        parameters.radiationSources[i].strengthRatio = strengths.values.at(i + 1);
     }
 }
 
diff --git a/source/EngineInterface/SimulationParametersEditService.h b/source/EngineInterface/SimulationParametersEditService.h
index 7ec7bfcb6..4ada3cd4d 100644
--- a/source/EngineInterface/SimulationParametersEditService.h
+++ b/source/EngineInterface/SimulationParametersEditService.h
@@ -7,19 +7,19 @@
 #include "Base/Singleton.h"
 #include "SimulationParameters.h"
 
+struct RadiationStrengths
+{
+    std::vector<float> values;
+    std::set<int> pinned;
+};
 
 class SimulationParametersEditService
 {
     MAKE_SINGLETON(SimulationParametersEditService);
 
 public:
-    struct RadiationStrengths
-    {
-        std::vector<float> values;
-        std::set<int> pinned;
-    };
     RadiationStrengths getRadiationStrengths(SimulationParameters const& parameters) const;
-    void applyRadiationStrengths(SimulationParameters& parameters, RadiationStrengths const& ratios);
+    void applyRadiationStrengthValues(SimulationParameters& parameters, RadiationStrengths const& strengths);
 
     void adaptRadiationStrengths(RadiationStrengths& strengths, RadiationStrengths& origStrengths, int changeIndex) const;
     RadiationStrengths calcRadiationStrengthsForAddingSpot(RadiationStrengths const& strengths) const;
diff --git a/source/EngineTests/SimulationParametersEditServiceTests.cpp b/source/EngineTests/SimulationParametersEditServiceTests.cpp
new file mode 100644
index 000000000..0dd03c1d4
--- /dev/null
+++ b/source/EngineTests/SimulationParametersEditServiceTests.cpp
@@ -0,0 +1,60 @@
+#include "EngineInterface/SimulationParametersEditService.h"
+
+#include <gtest/gtest.h>
+
+#include "Base/Definitions.h"
+
+class SimulationParametersEditServiceTests : public ::testing::Test
+{
+public:
+    SimulationParametersEditServiceTests() = default;
+
+    ~SimulationParametersEditServiceTests() = default;
+
+protected:
+    void checkApproxEqual(float expected, float actual) { EXPECT_TRUE(std::abs(actual - expected) < NEAR_ZERO); }
+};
+
+TEST_F(SimulationParametersEditServiceTests, getRadiationStrengths)
+{
+    SimulationParameters parameters;
+    parameters.numRadiationSources = 2;
+    parameters.radiationSources[0].strengthRatio = 0.3f;
+    parameters.radiationSources[1].strengthRatio = 0.6f;
+
+    auto strengths = SimulationParametersEditService::get().getRadiationStrengths(parameters);
+
+    checkApproxEqual(0.1f, strengths.values[0]);
+}
+
+TEST_F(SimulationParametersEditServiceTests, applyRadiationStrengthValues)
+{
+    RadiationStrengths strengths;
+    strengths.values = {0.1f, 0.3f, 0.6f};
+    strengths.pinned = {0, 2};
+
+    SimulationParameters parameters;
+    parameters.numRadiationSources = 2;
+    SimulationParametersEditService::get().applyRadiationStrengthValues(parameters, strengths);
+
+    checkApproxEqual(0.3f, parameters.radiationSources[0].strengthRatio);
+    checkApproxEqual(0.6f, parameters.radiationSources[1].strengthRatio);
+}
+
+TEST_F(SimulationParametersEditServiceTests, adaptRadiationStrengths_increase_allUnpinned)
+{
+    RadiationStrengths origStrengths;
+    origStrengths.values = {0.1f, 0.3f, 0.6f};
+    origStrengths.pinned = {};
+
+    RadiationStrengths strengths;
+    strengths.values = {0.1f, 0.5f, 0.6f};
+    strengths.pinned = {1};
+
+    SimulationParametersEditService::get().adaptRadiationStrengths(strengths, origStrengths, 1);
+
+    auto factor = 0.5f / 0.7f;
+    checkApproxEqual(0.1f * factor, strengths.values[0]);
+    checkApproxEqual(0.5f, strengths.values[1]);
+    checkApproxEqual(0.6f * factor, strengths.values[2]);
+}
diff --git a/source/Gui/RadiationSourcesWindow.cpp b/source/Gui/RadiationSourcesWindow.cpp
index 13bad531f..2c5fac8e2 100644
--- a/source/Gui/RadiationSourcesWindow.cpp
+++ b/source/Gui/RadiationSourcesWindow.cpp
@@ -87,7 +87,7 @@ void RadiationSourcesWindow::processBaseTab()
                 &parameters.baseStrengthRatioPinned)) {
             newRatios.pinned.insert(0);
             editService.adaptRadiationStrengths(newRatios, ratios, 0);
-            editService.applyRadiationStrengths(parameters, newRatios);
+            editService.applyRadiationStrengthValues(parameters, newRatios);
         }
 
         if (parameters != lastParameters) {
@@ -146,7 +146,7 @@ bool RadiationSourcesWindow::processSourceTab(int index)
             newRatios.values.at(index + 1) = source.strengthRatio;
             newRatios.pinned.insert(index + 1);
             editService.adaptRadiationStrengths(newRatios, ratios, index + 1);
-            editService.applyRadiationStrengths(parameters, newRatios);
+            editService.applyRadiationStrengthValues(parameters, newRatios);
         }
 
         auto getMousePickerEnabledFunc = [&]() { return SimulationInteractionController::get().isPositionSelectionMode(); };
@@ -238,8 +238,8 @@ void RadiationSourcesWindow::onAppendTab()
     ++parameters.numRadiationSources;
     ++origParameters.numRadiationSources;
 
-    editService.applyRadiationStrengths(parameters, newStrengths);
-    editService.applyRadiationStrengths(origParameters, newStrengths);
+    editService.applyRadiationStrengthValues(parameters, newStrengths);
+    editService.applyRadiationStrengthValues(origParameters, newStrengths);
 
     _simulationFacade->setSimulationParameters(parameters);
     _simulationFacade->setOriginalSimulationParameters(origParameters);
@@ -261,8 +261,8 @@ void RadiationSourcesWindow::onDeleteTab(int index)
     --parameters.numRadiationSources;
     --origParameters.numRadiationSources;
 
-    editService.applyRadiationStrengths(parameters, newStrengths);
-    editService.applyRadiationStrengths(origParameters, newStrengths);
+    editService.applyRadiationStrengthValues(parameters, newStrengths);
+    editService.applyRadiationStrengthValues(origParameters, newStrengths);
 
     _simulationFacade->setSimulationParameters(parameters);
     _simulationFacade->setOriginalSimulationParameters(origParameters);