It's best not to get caught in the mindset that there is a specific thinning ratio for paints and that to step outside this is to invite problems, because there ISN'T.
Paint consistencies vary between brands, colours within a particular manufacturer's range and even between different production batches of a given colour..
So, if you find that a particular colour of paint needs a little more or less thinner, the sky's not going to fall.
A given ratio may be used as a broad guide, but it's not set in stone and can and will vary depending on what effect you wish to achieve, your particular equipment setup and your individual painting technique/s.
The ratios which you are using with your Paasche H, for example, won't work for me because I use a different brush and my own individual technique tends towards very thin paint applied in multiple coats. Personally, I use much more thinner, moreso than most other people here, but that's what I'm used to and that's what works for me.
So forget the "magic number", and look at the consistency of the thinned paint before you pour it in your airbrush.