The problem with comparing weights is the scales that are used. mine appears to be accurate but its a $40 150lb ebay special so who knows. i also have a 10lb postal scale and even it will throw out an oddball number on occasion.
I sat all saws on the scales multiple times and checked the weight.
i didnt do that for my health.....occasionally this scale likes to show a number that isnt right so i always check weight several times. 6400 is the only saw in this test that my scale went screwy on....it went something like this...15 lb, 15lb 2oz, 15lb, 15lb. i threw out the 15lb 2 oz number and went with 15lb even. if it shows the same weight twice in a row i call it good.
I highly doubt any cheap Chinese scale could hope to be as far off as some of the weight numbers marketing has shown us. So I wouldn't worry much about it.