>After some further testing I came to the conclusion that the TRANSFORM function was pretty slow anyway. I decided to use to test the number of decimals and transform it onto character with the STR() function. To my surprise it was even faster than a single TRANSFORM function (more than 2 times faster). Since the routine i'm using is time critical, the solution I found is better than using TRANSFORM, even withouth the bug.

That's not too surprising, TRANSFORM is an old "picture function" - the type that we should be getting away from. I only use it in reports now when there is no reasonable alternative.