I had told Riley's first Vet how well he was doing going to the pad and she said he was doing that because he was so smart and that puppies don't have full bladder/rectal control until they are about 16-weeks old so perhaps you will start seeing some improvement soon...?!
I just googled to see if I could find anything ...
Found this:
* Be reasonable. Puppies can physically hold their urine for only about two hours. Puppies typically are not mature enough to control their bladders and bowels until about 16 weeks of age, and cannot be expected to be reliably housetrained until reaching 6 months old.
Dog Tip: Housetraining