I take your general point, however one small correction. The dynamic power term for Nad is PowerDrive.
For example, for the C375 BEE, power ratings are:
2 x 150W Continuous Power into 8 Ohms.
Dynamic power (formally Power Envelope, now Power Drive):
200W, 365W, 500W IHF Dynamic power into 8, 4 and 2 ohms, respectively.
With the Rowen mod, the amp will be stable down to 1 ohm with commensurately high Dynamic power.
The DDA-100 has 200WPC dynamic power into 4 OHMS, so about 130WPC into 8 ohms.