A friend had his O2 concentration set to 98% by the rock of the boat! He noticed around 60 feet...
That's highly unlikely. More likely the contacts somehow got bridged, the rocking of the boat did NOT change his setting.
I dived a SmartCom for a few years and hundreds of dives. Would I buy air integrated again? No, I find it highly unecessary, however, if you must have an air integrated computer this is not a bad choice. I found mine to be very rugged and reliable and have since passed it along to my girlfriend. I like the fact that everything you need is on one screen and you do not have to switch screens to view any info. The one constant beef you will here about them is they don't turn off wearing the batteries down, this has never happened to me, you have to store them in open air with nothing touching the contacts, no big deal.
You also mentioned you found a good deal, beware that if you do not purchase this computer from an authorized Scubapro dealer the batteries are not user changeable and very expensive. If you purchase from an authorized Scubapro dealer they will replace the batteries free for the life of the computer.