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I am in the market for a dive computer and have heard that the Scan 4 and the DataMax Pro are the same computer.  I was wondering to what extent that was true.  They appear similar on the surface, but are the algorithums the same?  I heard that the DataMax Pro had its algorithum updated last year, did the Scan 4 undergo the same update?  Also, In SCUBA Diving magazine they rewiewed air-integrated computers and listed the ascent rate of the DataMax Pro as 30,60,90 and for the Scan 4 they listed 60.  Can anyone account for the difference?  Thanks in advance...                 Trev