Depending on a lot of variables that are outside the code itself, it is possible that the time changes between runs, also if with the same code. Take for example when you first run it on your PC and when then you run it a second time shortly after: you could go from a first time of 2.10s to 0.8s, and that happens because the functions and the variables of the code are still saved in the RAM during the second run, while in the first they're not. A lot depends from the PC's prestation on the execution time, you could say that's beyond our control. Moreover in your case we're talking about a really small amount of time (which is per se a really good time, a lot of people (myself too) struggle to get slightly less than the average), so don't worry too much about it
