From my experience i find using a curve ball and hitting within the white circle has the same catch rate as hitting nice-great-excellent throws. From my experience using curve balls, razz berries and higher strength balls effect the chances. I used to think/assuming hitting excellent on a curve throw would garnetee a catch on a low level common mon even with gold medal bonuses to escape excellent throws even with great balls for the escape so many times vs. the high level rare mons to be caught with slow relaxed curves balls atleast hitting with the white circle. My tipping point was during starter event caught a lvl 28 snorelax near my workplace (only rare thing in area since i started playing) caught it 5 curved great ball throws, calm and relaxed, no nice,greats or excellent throws. Learnt from the only other time i saw something rare and fumbled 30 ultra balls mostly misses to have the f'r flee(dragonite). Also had what i used to call fluke catches on high lvl and cp mons like sedra/poliwrath/golduck/starmie/gengar i would assume would flee caugh within a couple curve pokeballs throws. Again low lvl common mons to escape back to back greats and even excellent throws. I also do believe the catch rates to get tweeked a little here and there but i tend to compensate for over the few hours/days after (if that makes sense)

PS 15170 catches, minus 1121 hatches and minus 2224 evolves = 11825 actual catches? (broke my lurkers vow. knew it would be on this 'sub' would be it (assuming thats right lingo :D )