Are the 901s and 4075 parts totally different for anyone but me? I have no luck interchanging them so I decided to use some of the 4075 parts that I have been sent after ordering the 901s and they are not even close to the 901s, IMO. The draw is SO hard!! 901 atomizer and 901 battery is great. 4075 atomizer and 4075 battery is a PITA!! What is the deal? Is it me?