Blending valdiation range

we had done blending valdiaton of drug substance and exciepient at 150 kg and at 70 kgs batch size

can we consider this as a minmum - max range and Blend any quantites in

between these ranges ?

Yes, you can do a bracketting and carry out such study. You need to know the procedure how to bracket that. Probably if you ask the senior members at your facility they may guide you as it requires whole set of confidential datas from both studies.