I think a new PQR is required for every new group number for dissimilar welds even if it is the same P number.

I'm not being sarcastic but if you are asking this question you have bigger problems than qualification.
Section IX may contain ambiguities, but it is quite clear on this. This is the most basic of the most basic of Section IX P-No qualification questions.

Nalla,

Question, why do you have incoloy in no. 1 a P no. 45, and in no.2 you have it as a P no.8, plus table QW-423.1 is if the Welder qualified to a P no. in the first column the second column is the P no. that he is qualified to weld, it is not for the wps or pqr.

strat

QW-423.1 applies only to performance qualifications.  The question seems to be on procedure qualifications.  Please clarify if you are asking about a WPS/PQR qualification range or a welder/welding operator qualification range.

The P-No. Group No. limitation is correct for procedure qualification when supplementary essential variables apply.  When supplementary essential variables do not apply, the limits of QW-424 are used and ASME IX P-No. Group No. is not limited.  A PQR made using Incoloy 825 to Incoloy 825 base metals would only qualify a WPS for welding P-No. 45 to P-No. 45.  A PQR made using Incoloy 825 to A131 Grade ? (unlisted base metal) base metals would only qualify a WPS for welding P-No. 45 to A131 of the same Grade.  These PQRs would not support welding procedures for P-No. 45 to P-No. 8, or P-No. 45 to P-No. 1.

If your question is on the substitution of base metals during the performance qualification test, then QW-423.1 can be used.  A welder qualification test made using a WPS for P-No. 45 to P-No. 45 could be performed with any P-No. 1 through 11, P-No. 34 or P-No. 41 through 49 base metal.  These substitutions are for welder/welding operator performance qualifications only and can not be used for production welds.