diff --git a/packages/effect-fc/src/Result.ts b/packages/effect-fc/src/Result.ts
index 42b0c1a..b496ce7 100644
--- a/packages/effect-fc/src/Result.ts
+++ b/packages/effect-fc/src/Result.ts
@@ -212,24 +212,24 @@ export const unsafeForkEffect = Effect.fnUntraced(function* <A, E, R, P = never>
     never,
     Scope.Scope | unsafeForkEffect.OutputContext<R, P>
 > {
-    const ref = yield* SynchronizedRef.make<Result<A, E, P>>(options?.initial ?? initial<A, E, P>())
+    const ref = (yield* SynchronizedRef.make(
+        options?.initial ?? initial<A, E, P>()
+    )) as Lens.SynchronizedRefLensImpl.SynchronizedRefWithInternals<Result<A, E, P>>
     const pubsub = yield* PubSub.unbounded<Result<A, E, P>>()
 
     const state = Lens.make<Result<A, E, P>, never, never, never, never>({
-        get get() { return Ref.get(ref) },
+        get get() { return Ref.get(ref.ref) },
         get changes() {
             return Stream.unwrapScoped(Effect.map(
-                Effect.all([Ref.get(ref), Stream.fromPubSub(pubsub, { scoped: true })]),
+                Effect.all([Ref.get(ref.ref), Stream.fromPubSub(pubsub, { scoped: true })]),
                 ([latest, stream]) => Stream.concat(Stream.make(latest), stream),
             ))
         },
-        modify: f => Ref.get(ref).pipe(
-            Effect.flatMap(f),
-            Effect.flatMap(([b, a]) => Ref.set(ref, a).pipe(
-                Effect.as(b),
-                Effect.zipLeft(PubSub.publish(pubsub, a))
-            )),
+        commit: value => Effect.zipLeft(
+            Ref.set(ref.ref, value),
+            PubSub.publish(pubsub, value),
         ),
+        lock: Effect.succeed(ref.withLock),
     })
 
     const fiber = yield* Effect.gen(function*() {
diff --git a/packages/effect-fc/src/SubmittableForm.ts b/packages/effect-fc/src/SubmittableForm.ts
index f83d579..a1f1009 100644
--- a/packages/effect-fc/src/SubmittableForm.ts
+++ b/packages/effect-fc/src/SubmittableForm.ts
@@ -53,27 +53,24 @@ extends Pipeable.Class() implements SubmittableForm<A, I, R, MA, ME, MR, MP> {
     ) {
         super()
 
-        this.encodedValue = Effect.succeed(this).pipe(
-            Effect.map(self => Lens.make<I, never, never, never, never>({
-                get get() { return self.internalEncodedValue.get },
-                get changes() { return self.internalEncodedValue.changes },
-                modify: f => self.internalEncodedValue.modify(
-                    encodedValue => Effect.map(
-                        f(encodedValue),
-                        ([b, nextEncodedValue]) => [
-                            [b, nextEncodedValue] as const,
-                            nextEncodedValue,
-                        ] as const,
-                    )
-                ).pipe(
-                    Effect.tap(([, nextEncodedValue]) =>
-                        self.synchronizeEncodedValue(nextEncodedValue).pipe(
-                            Effect.forkScoped,
-                            Effect.provide(self.context),
-                        )
+        this.encodedValue = Effect.all([
+            Effect.succeed(this),
+            Effect.succeed(Lens.asLensImpl(this.internalEncodedValue)),
+        ]).pipe(
+            Effect.map(([self, parent]) => Lens.make({
+                get: parent.get,
+                get changes() { return parent.changes },
+                commit: a => Effect.andThen(
+                    Effect.flatMap(
+                        parent.resolve,
+                        resolved => resolved.commit(Effect.succeed(a)),
+                    ),
+                    self.synchronizeEncodedValue(a).pipe(
+                        Effect.forkScoped,
+                        Effect.provide(self.context),
                     ),
-                    Effect.map(([b]) => b),
                 ),
+                lock: parent.lock,
             })),
             Lens.unwrap,
         )
diff --git a/packages/effect-fc/src/SynchronizedForm.ts b/packages/effect-fc/src/SynchronizedForm.ts
index 119d107..6f4777f 100644
--- a/packages/effect-fc/src/SynchronizedForm.ts
+++ b/packages/effect-fc/src/SynchronizedForm.ts
@@ -15,7 +15,7 @@ export interface SynchronizedForm<
     in out TEW = never,
     in out TRR = never,
     in out TRW = never,
-> extends Form.Form<readonly [], A, I, TER, TEW> {
+> extends Form.Form<readonly [], A, I, TER, TER | TEW> {
     readonly [SynchronizedFormTypeId]: SynchronizedFormTypeId
 
     readonly schema: Schema.Schema<A, I, R>
@@ -41,7 +41,7 @@ export class SynchronizedFormImpl<
     readonly path = [] as const
 
     readonly value: Subscribable.Subscribable<Option.Option<A>, never, never>
-    readonly encodedValue: Lens.Lens<I, TER, TEW, never, never>
+    readonly encodedValue: Lens.Lens<I, TER, TER | TEW, never, never>
     readonly isValidating: Subscribable.Subscribable<boolean, never, never>
     readonly canCommit: Subscribable.Subscribable<boolean, never, never>
 
@@ -78,7 +78,7 @@ export class SynchronizedFormImpl<
             Effect.succeed(this),
             Effect.succeed(Lens.asLensImpl(this.internalEncodedValue)),
         ]).pipe(
-            Effect.map(([self, parent]) => Lens.make({
+            Effect.map(([self, parent]) => Lens.make<I, TER, TER | TEW, never, never>({
                 get: parent.get,
                 get changes() { return parent.changes },
                 commit: a => Effect.andThen(