I noticed the same with my premier balls. I like to keep a ton of em around for spamming when I'm feeling too cheap to use an actually valuable ball, and
I've noticed the catch rates seem to be a bit more harsh with them. There's nothing we can do about it though, just keep chucking balls i guess.
Also, I just have to say, that ditto really said HA to you, too. XD
Breeding at its best is my pursuit! If I don't have it, tell me because I might just want to get it myself! I breed with egg moves intact, so let me know if you're interested in anything specific!
I have all starters up to gen 5, as well as many DWF pokemon such as Dratini, porygon, eevee, bagon and more!
I'm currently seeking: Jirachi, 2011 Suicine & shinys!