The percentage markings look like a way to make the solution stronger. For example at 1:10 you have a 10 percent solution. By filling to the 10 percent line you add 10 percent. So you would now have a 20 percent solution (or, in this case twice as strong).
At 1:7 you have a little over a 14 percent solution. Add up to the 10percent line and you will have a little over a 24 percent solution.
What you need to realize is that using this feature does not make the concentration 10 percent stronger. It increases the concentration of the chemical added to a 10 percent higher level. This will typically make the concentration much stronger. I don't think you would have much use for this feature in mixing detailing chems.
Thanks for getting back. I did make use of the A and B lines and it helped me.
I will ignore the 10-25% marks, since I have no use for it right now. And yes you are correct, I picked the container from a shop, which sells auto paint primarily, so they may have a use for it in their sector.
In a paint shop application, they would use it to mix paint and catalyst. You adjust the amount of catalyst depending on heat/humidity levels. It could also be used for adding in retarder/reducer, for areas that need that added in.