LibreOffice Calc’s ROUND function uses the round to nearest, ties away from zero (or round half away from zero) rounding method. This is not the rounding method recommended by IEEE 754-2019 and ISO/IEC 60559:2020, so my first question is: is there a function in Calc that uses this rounding method?

I wasn’t able to find a positive answer for the above, but I found this and this other threads. Unfortunately all the suggested formulae are either wrong or work only for integers or cents, so I made a Calc document with sources and a comparison between rounding methods (1st sheet) and hopefully correct methods to round numbers with the round half to even rounding method mentioned above, to a specified decimal digit (2nd sheet) or significant digit (3rd sheet). I tried to make it with as simple steps as possible, while commenting them as best as I could. I have some questions regarding this document:

- are there combinations of numbers and digits to round to that return an incorrect value?
- is it possible to simplify the number of steps and/or change them to get rid of machine errors?
- is it possible to make user-defined functions that will work on every spreadsheet instead of having to use a few cells to store variables for every number I want to round?

Thank you in advance.