Why ERPNExt round odd up, even down (3.5 to 4, 2.5 to 2, -3.5 to -3, -2.5 to -3)?

Why ERPNExt round odd up, even down (3.5 to 4, 2.5 to 2, -3.5 to -3, -2.5 to -3)?
Any reason?