Top benchers is the list for raw, absolute 1RM (actual or calculated) numbers, i.e. if you can lift 100kg 1 rep, your number in that list will be 100
Top benchers by BW takes into account your weight, so it's a power to weight ratio, i.e. if you can lift 100kg 1rep and you're 50kg, your number in that list will be 100/50 = 2.00.
To quality into the long hu bang, you have to submit at least 2 out of the 3 big 3 lift numbers. I've linked to a 1RM calculator in the original post in case you don't do 1RMs(like myself). You can use that to calculate your 1RM based on however many reps you usually do, before submitting.