I agree with you, I got this from a book, Weather Predicting Simplified by Micheal William Carr. On page 23, I'll parapharse in addition a low- pressure system is rapidly intensifying if its central sea-level pressure drops at least 24 mb in 24 hours at 60 degrees latitude. At other latitudes the sea-level pressure drop is multiplied by a correction factor of sin (latitude of a low's center)/ sin60. For example, at 40 degrees north the factor would be sin40/ sin60, or 9.8/9.9, which equals 0.989. Then since there are 24 hours multiply that by a pressure drop of .989 an hour to get 23.7mb(pg. 23, Weather Predicting Simplified). He is saying that the pressure drop is a factor of the latitude in degrees, maybe he thinks, as you travel further away from the equator pressure drops faster but why?

Edit: I found this website on it http://weather.ou.edu/~mbergman/bombcyclogenesis/index2.html