Information on Cary CAD 300 SSE

I'm new to the use of vacuum tube amps and have a question. Im currently using the Cary CAD 808R ( Rocket 88R ) with which I'm very happy but I'm also interested in trying SE or OTL amplification. I'm aware of the Cary 300 SE monoblocks through various reviews, and am impressed with reviews and explanations regarding the Atmasphere S-30 OTL. The S-30 may be a little outside my budget right now but a friend just came into a Cary amp that he described as a 300 SSE that he is willing to sell. I've been unable to find any literature using that model designation but he described it as a limited edition model which is, essentially, two 300 SE monoblocks combined into one chassis with an upgrade in power over the SE's.

Because the SSE is rare and, I assume, relatively expensive, why would one not simply buy the SE pair with more latitude in placement unless the increase in power is significant and important to one's overall setup.

Although I'm not requesting advice regarding my system in general, FYI, I will be using my Peachtree Nova as preamp and the MMC Serie reference 3A speakers.