Xcode4: Different code generated for custom core data managed objects

Now that Xcode4 is publicly available I'm moving this question out of Apple's secret dev forum:

Can someone explain why the code generated in the following procedure is different than in Xcode3? Is the code better or might this be a bug?

I use Core Data custom managed classes and this was the procedure I followed in Xcode3:

1. Go to the model editor
2. Select the entity you wish to generate source code for
3. Go to File->New->New Files
4. Choose managedobject class (or whatever it was, I can't open xcode3 anymore to verify)
5. Select entities you wish to generate (the previously selected entity in step 2 is checked off)
6. Click Finish

Now, in Xcode4, I THINK this is how to do it, but I'm not sure because it generates different code:

1. Go to model editor
2. Select entity
3. Go to File->New->New File
4. Choose "NSManagedObject subclass"
5. Choose location and create.

The code it is generating is different for a number of reasons:

1. The generated code for adding and removing members of a set in the entity are no longer declared in the @interface, but instead @implementation. This causes code sense to fail detecting these methods.
2. The same generated code for adding and removing objects is now fully defined, no longer autogenerated using CoreDataGeneratedAccessors

For example, Xcode3 would have generated this code in the HEADER file:

@interface SampleEntity (CoreDataGeneratedAccessors)
- (void)addChildObject:(Child *)value;
- (void)removeChildObject:(Child *)value;
- (void)addChild:(NSSet *)value;
- (void)removeChild:(NSSet *)value;
@end

Now, Xcode4 generates this code in the IMPLEMENTATION file:

@implementation SampleEntity
@dynamic children;
- (void)addChildObject:(Child *)value {    
    NSSet *changedObjects = [[NSSet alloc] initWithObjects:&value count:1];
    [self willChangeValueForKey:@"children" withSetMutation:NSKeyValueUnionSetMutation usingObjects:changedObjects];
    [[self primitiveValueForKey:@"children"] addObject:value];
    [self didChangeValueForKey:@"children" withSetMutation:NSKeyValueUnionSetMutation usingObjects:changedObjects];
    [changedObjects release];
}

Can someone weigh in on why this is different? Xcode4 code sense does not like this new way of generating NSManagedObject subclasses.