This is a case where it’s important to look at things relatively-
Capaldi’s Seasons never had an AI score above 85. (And he only ever had 4 episodes hit 85.)
In Smith’s run he only ever had 6 episodes that went below 85 in AIs. (And only two episodes below 84.)
Tennant had 7 episodes below 85 in AIs...but none below 85…