When using the @ROUNDM() formula in my spreadsheets occasionally the formula decides to add the multiple I have chosen to round up by when the number doesn't need to be rounded as it is already a multiple of the required number for example : if I required a cells contents to be rounded up to the nearest multiple of 5 then entered 15 in that particular cell the formula would return 20 yet, 15 is already rounded to the nearest multiple of 5. Is anyone experiencing similar problems or can anyone provide a solution?
I use Excel, but from what you have said in your post, the function @ROUNDM() is behaving correctly in that it is taking your number 15 and rounding it up to the next multiple of 5, not the nearest but the next.
In Excel the function is RoundUp. If I wanted the nearest then I would need to use Round.
Check and see whether there is a similar function in your spreadsheet