50% paint color

Ok up until this week I have only heard of people using paint colors at 50%, now what does that mean ? Well when a color is made using universal tints by a computer at a paint counter it is done is measured out predetermined amounts. When you ask for 50% strength of a color they punch that into the computer.
 Let's say your color requires 40 yellow 30 blue and 20 black for the purposes of example only , 50% of that color would be 20 yellow 15 blue and 10 black added to a can of untinted paint. That's it .
For me I loved the color and tone of BM revere pewter but it seemed too dark for the look I wanted so I thought maybe at 50% strength it would be perfect , it seemed a better option than trying to find a totally different color.
So if you like a color but think its too dark or deep or bright , try it out at 50% , I swear they will know what your asking for at the paint desk.