The entirety of that catalog you linked to shows a bias toward DVD-R. There are many more options for DVD-R than for DVD+R. I'm guessing this is a response to market demand, and/or their way of streamlining operations.
I'm of the thought that MCC 003 and MCC 004 generally scan better than MCC 02RG20 and MCC 03RG20, with performance being roughly equal.
But yeah, the "professional" title means just that -- for professional/prosumer use. No guaranteed quality difference (maybe there's tighter quality regulation or a different kind of warranty). And since many businesses want unbranded, printable media, that's what they provide.
That it gets branded as DataLifePlus is just a guarantee that it's AZO (which, for the most part, means MCC/MKM codes). Compare to having to make sure you get AZO discs when ordering regular consumer media, where the packaging and naming is very similar across variants.