diff --git a/get-build-number/get_build_number.sh b/get-build-number/get_build_number.sh
index eb38f35a..13155b71 100755
--- a/get-build-number/get_build_number.sh
+++ b/get-build-number/get_build_number.sh
@@ -149,7 +149,7 @@ if [[ "$MAX_CLAIMED" -eq 0 ]]; then
       fi
       echo "Seeding from legacy build_number property: ${LEGACY_BUILD_NUMBER}"
       # 10# forces base-10: a leading-zero property value would otherwise be parsed as an (invalid) octal literal.
-      MAX_CLAIMED=$((10#$LEGACY_BUILD_NUMBER + 1000)) # buffer against the legacy property still advancing elsewhere during migration
+      MAX_CLAIMED=$((10#$LEGACY_BUILD_NUMBER + 10000)) # buffer against the legacy property still advancing elsewhere during migration
     fi
   fi
 fi
diff --git a/spec/get_build_number_spec.sh b/spec/get_build_number_spec.sh
index 8312a99c..86e70bfc 100755
--- a/spec/get_build_number_spec.sh
+++ b/spec/get_build_number_spec.sh
@@ -75,8 +75,8 @@ Describe 'get_build_number.sh'
     When run script get-build-number/get_build_number.sh
     The status should be success
     The output should include "Seeding from legacy build_number property: 42"
-    The output should include "Claimed build number 1043"
-    The contents of file "$BUILD_NUMBER_FILE" should equal "1043"
+    The output should include "Claimed build number 10043"
+    The contents of file "$BUILD_NUMBER_FILE" should equal "10043"
   End
 
   It 'should return an error if the legacy build number property is invalid'