This is why we offer a step process when paint correction is needed. You will need to go over everything again if you want a flawless shine.
Because you didn't use the proper cutting pad and compound it didn't break down heavier scratches. Its always best to test a 2x2 ft section to see were you need to be at with what pad and compound will break down the paint to a smooth finish. I cant stress this enough. Paint correction can not be achieved with one or two bottles of compound/polish. You need to bring the paint from a 1000-1500 grit level to around 3500-4000 grit level. You can not start in the middle unless you are very experienced in inspecting the paint. Novice need to refer to above and test!
The porter cable is more then powerful enough, with the proper pad and compound/polish.
PM us if you need any help.