foley balloon size

I have a question about the balloon in the foley cath. I have recently moved to a new state, and here they seem to use a lot of 30 cc cath sizes. I am not used to using this size of cath for everyday cath patients. These patients seem to "leak" a lot. It was my understanding this bigger bulb cometimes causes irritation in the bladder and can make the bladder spasm more and thus the leaking? or am I totally wrong here? I am a home health nurse, and these patients are long time foley cath patients, and long time "leak" patients too. I am not sure. I am just always used to using the standard 10 cc bulbs.

any information would be great.

thanks.