Hello!! Sorry to be getting back to your comment so late!!
To be honest, I've had three tiels over time (a brother and sister, and then another girl), and clipping their wings for all of them seemed to help! When birds have their wings long and can easily escape from the owner it gives them a sense of independence, and it's almost as if they realise they have an advantage over them! Once they realise they have that advantage, they can get a little bit of an attitude.. You can definitely give it a shot, and maybe if at all possible/if you aren't doing so already, spend some time with them! Tiels are really curious birds, so if you just talk to them often or let them stroll around the house with you on a shoulder or something, it'll keep them entertained while you take care of things! I let my boy sit on my shoulder while I do paperwork or clean the house or something, and if I can't let him stay on my shoulder (like if I'm cooking) I let him sit by the window (closed of course
) for him to squawk at the passerby people~
heh, sorry to go overboard on the response, but what you read online definitely is true, and I'd definitely go for it if you haven't already! Hope this all helps!~