I'm just going to go with not worrying about it. I've had these orchids for a few years now and things have been fine. I don't need to go looking for trouble that's not there.
Something tells me you're goig the right way.
Just keep monitoring their growth and watering needs and see how it goes.
I wish my humidity was 40%. I use RO water in my humidifier, if I didn't I would have white powder over everything. I haven't had much luck with having them last to long. Only the one I have downstairs for my Masdies. I have had that one for years. My orchids seem to be doing pretty well for my low humidity.