Dishonest fee increases after rides.

I have spent the majority of last year, and into this new year, checking my final ride price from uber. This after I noticed that almost always, the fee I book with, ends up increasing by an average of 30%. I have tried to raise this issue, uber gives the same response, on how the actual distance and time changed between their estimates and actual. Here is the thing, their estimated drop off time is very accurate, why is the final fee different then? What is worse, is getting this 30% price increase for the same ride over and over, as I like to go to a specific area and back. Uber keeps sneaking in an above 20% increase without any traffic issues or poor routes by its drivers. Someone should research this and see if it is not an algorithm targeting specific groups of society. I suspect it is, just like their discounts.