Hi, thank you for being our customer and for your review.
We really appreciate your opinion.
As for your questions:
The arbitrage charts/numbers does not include any fees and costs associated with different exchanges.
While we understand that integrating those fees would be of greate use for traders this was not our main priority. And also different exchages do have different fee schedules which may depend on several factors for each trader individually. Some of them not. Which makes the task on supporting fees and costs in caculation more complicated.
Currently we assume the simpliest variant when each person calculates his percent of fees and costs and just applies them to the naked percent difference we caclulated base only on orderbooks of exchanges.
Once again we caculate price based only on orderbooks.
It would be good to mention once again that our caclulation algorithm repeats the matching engine of the exchanges to caclulate which orders will be filled in order to sell/buy 10, 100, 1000 ... BTC. The main point was and is that it is not obvious that when matching engine performes matches for limit order not all matched orders are filled with the same price. Thus final price of your sold/bought BTC cannot be caculated by multiplying your order price and volume.
Instead you have to summ up all matched orders prices and volumes and caculate average price which will be the actual price of you filled order.
Here is an example of how we caculate price of the filled 10 BTC order.
If you still have questions feel free to ask them here.
As for your other quesions thy are too general can you probably be more specific?
Once again thank you for sharing your experience and being our customer.