PP Read Master Data, Bom Usage

Hi,

I've defined a new production order type AA01 and new BOM usage Z and have variant configuration. I want to explode Z BOM's within AA01 production order. Everything ok when creating production order, system explodes the BOM with usage Z. But when reading PP master data for a saved order can not explode the BOM with usage Z and explodes usage 1. What's the difference between creating and reading pp master data.

Regards,

Emre,