Clarification regarding Thickness range

[K K]

Dear Experts,

Please need your response on my doubt.

PQR Details as below - ( For piping line classes ASME B31.3 and Sec.IX ).

Base metal Thickness - 30.96mm 

 Impact Tested with - @-29°C

PQR Based on a dual process GTAW+SMAW ( 4.0 mm+26.69 mm).

Material - ASTM A106 Gr.B

My Doubt as below - 

Shall I use the range in my WPS - 

Base metal Thickness - 25.4 mm to 36.96 mm.

dual process GTAW+SMAW  Range - 8.00mm to 28.96mm. 

OR

 Shall I follow QW-403.6 and for Impact test Shall  refer range - ASME B31.3 Table 323.3.1 (A-5) T/2  to T+6 mm.

Or

If I need this qualification - the above mentioned range in WPS is acceptable -  ( i.e - 25.4 mm  to 36.96 mm).

Please give me your response on my doubt with code reference. 

Thanks in advance.

Regards 

Kiran