As anticipated, now the second new provincial court has been officially created as well. Published on January 21, the announcement titled พระราชบัญญัติจัดตั้งศาลจังหวัดที่อำเภอพระประแดง จังหวัดสมุทรปราการ พ.ศ. ๒๕๕๓ officially created the new jurisdiction, becoming effective the day after publication.
As Richard Barrow found out, this does not mean that the new courthouse started operation already. The article in the Prachachat newspaper says that before starting operation it needs another royal act, until then all cases in the jurisdiction of the new court (i.e. the district Phra Pradaeng and Phra Samut Chedi) will still be handled by the provincial court Samut Prakan.
So, by this act the Ministry of Justice is entitled to build the new courthouse and hire the personal, the date it will actually start operation isn't publicly set yet.