Ok, I understood it the other way around, here is the example from their website

"The example of Switzerland: With a cost of living index of 126 all goods are on average about 26% more expensive than in the USA. But the average income in Switzerland of 7,923 USD is also 18% higher, which means that citizens can also afford more goods. Now you calculate the 26% higher costs against the 18% higher income. In the result, people in Switzerland can afford about 6 percent less than a US citizen."

So it means that with PPI 94 if you come to Switzerland despite higher salary you will only afford 94% of your existing 100% in US. So it means, if you want to afford more you need to look for a 100+ PPI. Or what am I missing?