Regarding the AMPOWDER command, why is the entry for the powder convection coefficient different from the value entered in the Details window for AM Process > Build Setting?
The difference in the convection coefficient is likely due to a unit conversion from what's displayed in Mechanical software (W/mm2 * ̊C) to the solving units (tons/second3 * ̊C).
See this document on solving units: Understanding Solving Units (ansys.com)