Keep in mind though that alot of the times the 'drops' are 'vanity drops'. Meaning, a suit tagged 40R Drop 7 may have a 34' waist. RLBL is one of the only brands with perfectly corresponding drops between chest size and trouser waist (i.e. 40R suit with 33' trousers on a drop 7).
Also, a high drop can be an indication of a slim cut. A suit with a drop 8, 9 or 10 will likely have narrow armholes.