As can be seen, class XII marks receive only 15% of the weightage (whereas the CAT percentile receives a significant (67%) weightage). Furthermore, a 70% in class XII will result in 6/10 points in that section. As a result, a person scoring 80% or higher has an advantage of only 4 points out of 10 in a section with a weightage of only 15%.
As a result, a low class XII score of 70% is not a particularly important factor in shortlisting, and it is easily compensated for by a high CAT percentile.