Keep in mind the angle of the press is NOT the angle of your seat. The seat obviously directly influences it and is what makes you comfortable and consistent BUT what i tell people when im teaching them is that it has less to do with your seated angle and more to do with the angle of your chest. Think of it this way, how many do you see doing a flat bench press who have arched their back so much its now more of a decline press. Same thing with incline, you arch your back out it will flatten the angle of your chest and you loose some angle. Add plates under the legs or angle your back out to flatten your chest out (go from 50 degrees to more or a 45 that you say you want). Just make sure its a light and safe back arch and not something that will hurt you.