The ratios given by manufacturers is usually the theoretical best case scenario of how much the injector can draw. As in, lowest rated flow rate (on a 2-4 gpm injector, they’ll rate it based on a 2gpm machine), no back pressure from long hoses, short soap tube, etc.
In real life, they will draw a lot less.
But @Innocentbystander is correct. Ratios don’t matter for most situations.
If the growth on the siding is turning colors and starting to come off within 5 minutes or so, your mix is good. If it sloughs off 30 seconds after it hits the siding, it’s too hot - add some water. If it’s not budging after 5-10 minutes of dwell, it’s too weak. That’s all you really need to know for washing in the real world.
