diff --git a/prototype/doubt-difftool/main.swift b/prototype/doubt-difftool/main.swift
index 623f4cf36..658912982 100644
--- a/prototype/doubt-difftool/main.swift
+++ b/prototype/doubt-difftool/main.swift
@@ -178,7 +178,8 @@ let parser = parserForType(aSource.type)
 
 let a = try benchmark("parsing source a") { try parser(aSource.contents) }
 let b = try benchmark("parsing source b") { try parser(bSource.contents) }
-let diff = benchmark("diffing") { Interpreter<Term>(equal: Term.equals(annotation: const(true), leaf: ==), comparable: Interpreter<Term>.comparable { $0.extract.categories }, cost: Free.sum(Patch.sum)).run(a, b).flatMap(refineLeafReplacement(aSource.contents, bSource.contents)) }
+let initialDiff = benchmark("diffing") { Interpreter<Term>(equal: Term.equals(annotation: const(true), leaf: ==), comparable: Interpreter<Term>.comparable { $0.extract.categories }, cost: Free.sum(Patch.sum)).run(a, b) }
+let diff = benchmark("diffing within leaves") { initialDiff.flatMap(refineLeafReplacement(aSource.contents, bSource.contents)) }
 switch arguments.output {
 case .Split:
 	let JSON: Doubt.JSON = [