Your sincerity and desire for doing some service for Krishna is very much encouraging to me. Please go on chanting nicely, and steadily. Chanting 16 rounds is prescribed, but you can chant more rounds and hear them very attentively.
If you are not satisfied with your cooking engagement, tell Brahmananda to give you some other engagement. But it doesn't look well if you change from one center to another for some convenience. Everywhere service to Krishna is the same, but if you are feeling some inconvenience, then you may inform Brahmananda, and get some relaxation by change of duty.