h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

on page http://www.bbc.co.uk/dna/h2g2/A810244 the following is stated,

"Partial pressure is the total pressure exerted by a gas in a mixture of gases and is equal to the sum of the partial pressure that each member gas has and would alone have if the other gases were absent. The air we breathe is a mixture of 79% nitrogen, 20% oxygen and 1% other gases consisting mainly of argon but small but important traces of carbon dioxide and water vapour. Therefore, the partial pressure of nitrogen in the air at sea level is 790 millibars.

As a diver descends in water the ambient pressure increases at a rate of one bar for every ten metres. So at a depth of ten metres, the partial pressure of nitrogen is 1.6 bars, at 20 metres 2.4 bar and at 30 metres 3.2 bars. Therefore, a diver at a depth of 30 metres breathing compressed air is subject to nitrogen narcosis".
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Surely this should read "at a depth of 10 metres the pressure should be 790+1000 = 1790 (1.790 bars), at 20 metres 2000 + 790 = 2790 mb (2.790 bars), at 30 metres 790+3000 = 3790 mb (3.790 bars) or am I missing something ?