It is a "modified 2 stage" system. Low can run for the first 5 minutes, or 1-12 minutes at the BEGINNING of the cycle. To me, this is a soft starting single stage.
I guess technically it is a 2 stage, but it misses 90% of the benefit of 2 stage. Any furnace that can't run high first then low, in my view (energy and comfort), misses the point.
Ideally a 2 stage can cycle back and forth, modulating in an attempt to match envelope losses.
(
http://site.mypointnow.com/documents/25-k120602.pdf p12. Also, notice it doesn't even list a low output on spec sheet. )
The real problem comes in when the sales person who like to oversize doesn't understand how this turd operates. He figures he can size to low stage and have "high for fast recovery". Now you have a grossly oversized piece of equipment you can't even lock on low.
I Audited a house with one of these. 2200 sf, 120,000 btu. Client replaced a 30 year old furnace a year before I got there (same size of course). Bill analysis showed NO ENERGY SAVINGS and they have all kinds of comfort issue.
IMO, calling it 2 stage is like painting a dog turd gold and calling it a gold brick. Makes true 2 stage devices look bad by association.