Excel not subtracting properly causing "un-rounding"

[nshepo20]

Through my entire process, I round everything with the Round formula since these numbers are designated to be $s to go into an ERP system that should have everything rounded to the 2nd decimal place. The final step in my process is subtracting my post-process rounded side to what it should actually be rounded and re-allocating the difference. For some reason, there becomes a negligible amount not rounded after this subtraction causing a float variable. I can easily just round this number too so it's nbd but I just need to know how is this even possible? Is this an Excel bug?

Both pivot tables are filtered for the same item and yes I double checked that the pivot tables were pulling from fields that were rounded with "=ROUND(W122,2)" formulas. See the pictures below! Thanks in advanced!

 

[Jeffrey Mahoney]

I don't exactly how or when you're doing the rounding. I find that when I try to round numbers within the early calculations, it causes major issues. My last result is rounded so as to not cause variances like that.

 

[offthelip]

It is worth while reading this article about how excel stores floating point numbers because I think you will find it answer your query:

Floating-point arithmetic may give inaccurate result in Excel - Microsoft 365 Apps

Discusses that floating-point arithmetic may give inaccurate results in Excel.

learn.microsoft.com

 

[Joe4]

Yes, this is a known situation, that is outlined in offthelip's reply.
Best bet is to round the final value.

 

[nshepo20]

It is worth while reading this article about how excel stores floating point numbers because I think you will find it answer your query:

Thanks Joe! I read the part "Repeating binary numbers and calculations that have near-zero results" and that seems to explain it! Pretty fascinating and cool to have learned something new today. I will be sure to round the final results for now on as everyone suggests

 

[nshepo20]

It is worth while reading this article about how excel stores floating point numbers because I think you will find it answer your query:

Thanks offthelip! Very interesting to read and explains this issue. Much appreciated!