It is not doing arbitrage.
If using buy:
It will check the order book of sellers, it will take the first one in the list: the lowest sell order, and buy it up to the max quantity set.. then it will wait until the timer expires and do it again. So if your max is 10 and the order has an 8 there, it will buy 8 then wait until the timer is over then check the order book again if the first order is 11 it will buy for 10 and then wait for the timer.
The sell bot does the same just in reverse.