Thats a pretty huge drop. Mine typically fall about one tenth from tapers/technical adjustments and adrenaline. Also I guess this could be highly individual. Some people tend to be way more inconsistent technically than others. My teammate ran a pb of 7.19s in the heats and a 7.31s in the final, he is terribly inconsistent from meet to meet. Whereas I tend to be quite consistent from meet to meet and race to race, maybe .02s between heats and finals and between meets if that even. The only significant time drop within season that I’ve ever experienced came from a technical adjustment to my start which made me jump from consistent 10.9s, to 10.7s. Other then that, conditions and competition and slight progressions will advance my times.