[Iska]

Но я так понял, что это обычное бухгалтерское округление тоесть Round(2,5) = 2 »

Да, это т.н. банковское округление, или округление к ближайшему чётному:

The Round function performs round to even, which is different from round to larger. The return value is the number closest to the value of expression, with the appropriate number of decimal places. If expression is exactly halfway between two possible rounded values, the function returns the possible rounded value whose rightmost digit is an even number. (In a round to larger function, a number that is halfway between two possible rounded values is always rounded to the larger number.) Round to even is a statistically more accurate rounding algorithm than round to larger.