Hi and welcome to forum!
Thanks for your suggestion for removing mould odour. I have never experienced it myself, perhaps I'm lucky. My usual habit is to turn AC off a few minutes before arrival, leaving the fan on, in the belief that the moisture condensed on the relevant AC part is dried off by the time I get home.
I'm not sure about your cleaning method. I'd be cautious about introducing cleaners intended for the bathroom to a metal, brass is it?, heat exchanger. Let's see the ingredients of BAM shower spray:
http://www.rb-msds.com.au/uploadedFi...3-D0279548.pdf
Cheers