There are 2 potential causes for the need for a negative strain scaling factor. In some alloys, there is a phase change that actually swells the part. Or a user may improperly build the part with beam offsets that overcompensate for shrinkage. If it was maraging steel, than a negative strain scaling factor is actually physically realistic. For 316L, the user needs to follow the recommended approach for building the part. A negative strain scaling factor will be availalbe in 2019 R3 for alloys which swell.