Different Results Based on whether summarize comes before or after formula tool

Question

Hello,

I have ran into a unique situation where I am getting a different result from a workflow based on whether the summarize tool comes before or after the formula tool. The even more interesting (and frustrating) part is that i have seen the reverse of this occurring with other files (i.e. the data balances in other files when the tools are in a separate order). Is there something I am missing? I have attached a workflow showing these outcomes.

Thanks,

Rounding Issue.yxzp

Qiu · Answer

@Zas3nfkb 
I partially agree with @apathetichell , which is the precision issue of Double Data type.
and there is some significant large number in your dataset such as "224861230037319988675608576.00", which is believed to be beyond alteryx limites as per alteryx help below.
I tried with a sample of 10K rows, and it works just fine.
I recall in the school days, which is quite long time ago, teacher told us to try not use extremly big or small numbers as much as possible.
So in your case, do the Formula Tool first to reduce the order to the data then do Summarize is an correct way, it appears.

apathetichell · Answer

https://stackoverflow.com/questions/9911016/double-subtraction-precision-issue