Dissimilar Base Metal Thickness qualification accordance with QW-202.4 (b) ASME IX

QW-202.4 (b) said: for P-No. 8, … metal, there shall be no limitation on maximum thickness of thicker production member?

Does a combined WPS qualification make production on maximum thickness? Thickness limit to be extended beyond the limit specified in QW-451.1?

No, a combined WPS shall not be allowed max. thickness qualification.
See note 1 in QW-451.1.