As you can see, the RT value is significantly bigger then the TAT value. As you can see, the RT and the TAT values are almost identical. It changes it because of blunt nose which is often covered with a tip that's made of a special materials. Ofthen there are soft metals with the big Constant of Friction. Of cource, blunt projectiles are inferior to sharp projectiles if used against vertical armor.
Lets analyze one simple example.
A projectile with the sharp nose engages with the King Tiger's frontal armor. If it less than 235 mm our projectile won't penetrate the King Tiger's armor.