I Am Thinking About Switching From Vestura To Chateal For

I am thinking about switching from vestura to chateal for major monetary savings and the only difference I found is the type of progestin. Vestura uses drospirenone whereas chateal uses levonorgestrel. When I went to research the difference I found that levonorgestrel is used in plab b. Is this a normal thing found in birth control or is this only supposed to be used as an emergency contraceptive?