Just to confirm your resoults! Tested qith QuickDesk and IBObject, server is FIrebird RC2.
I've added a primary key column to your table to use in IBO
CREATE TABLE NEW_TABLE (
MONEY1 NUMERIC (18, 4),
MONEY2 NUMERIC (9, 4),
MONEY3 NUMERIC (18, 5),
ID INTEGER NOT NULL);
ALTER TABLE NEW_TABLE ADD CONSTRAINT PK_NEW_TABLE PRIMARY KEY (ID);

The resoult is the same you got :((
I've also added a MONEY4 NUMERIC (18, 6), and it's wrong like MONEY3 is, so there is something is break above scale 4 code.
Very fringthening
Regards
Marco Menardi