TL;DR
Is pricing my app (iOS/Android) based on PPP (purchasing power parity)[0] or the Big-Mac-Index[1] a good idea to mitigate the overpricing in poorer countries resulting from Apples/Googles currency based conversion?Background:
Hey, I'm Maximilian, the solo founder of boost (shameless plug:  Even though my app is currently completely free to use i investigated how to size my pricing tiers in the future. In the process i came across a number of app ratings of competitor apps coming from poorer countries saying the respective app is nice but way too expensive for a local.Problem: 
That got me thinking - Apple, as well as google are currently loosely converting each pricing tier based on currency and taxes. This makes apps overpriced per default when e.g. my yearly subscription of $89,99 in the US is ₹6,000 in India ($80.46 converted)Question(s): 
To price my app fair and in a way that it's perceived cost is equal in regards to local purchasing power i thought about factoring in PPP (Purchasing Power Parity index) or the Big-Mac-Index[1].
Has anyone experience with adjusting prices of a digital product to local purchasing power in general? Is the fear of arbitrage or people from richer countries buying products in foreign App-Stores the reason this is not done?[0]Purchasing Power Parity: 
[1]Big Max Index: 
[2]My app: 