For all those complaints about this at least they are counting 1GB = 1024MB and 1MB at 1024KB vs. 1GB=1,000,000,000B ; this is per the historical usage page. If you do the math, for the 150GB/month plan that amounts to 11,061,273,600 bytes additional you get by calculating this way. And for the 250GB/month plan it amounts to 18,435,456,000 additional bytes per month.
1K.....1,024................1,000
1M.....1,048,576..........1,000,000
1G.....1,073,741,824.....1,000,000,000