OOP: Measurements of book 5 don't add up?

[thegreatwebguru]

No: HPFGUIDX 60797

My copy of GoF measures in at 9.2 x 6 x 2.25 (HxWxD) and Yahoo has 
OoP measuring in at 7.8 x 5.1 x 2.5 (HxWxD). 

I just don't understand how it is 1/3 longer if it is shrunk in 
length and width, and only a quarter of an inch thicker? 

Does this mean the text is considerabley smaller, or more 
condensed? 

Does this also mean that this book will not be flush in my book self 
next to the other books? 

OR, are these or my measurements off?

--Waluigi

(I hope this isn't off topic....sorry if it is)