A long time later, this is in fact true.
Figure 1: Arya Stealth blocked ear canal measurements for all four Dekoni pads. NS: New Stock pads. DES: Dekoni Elite Sheepskin. DEH: Dekoni Elite Hybrid. DEV: Dekoni Elite Velour. DEFS: Dekoni Elite Fenestrated Sheepskin.
Figure 2: HE1000se blocked ear canal measurements for all four Dekoni pads.
At least for my ears, the lower treble is generally relaxed, but the 6.5 kHz peak remains. The memory foam material or extra seal improves linearity, getting you about 1 dB more at 20 Hz, but less between 40 Hz to 150 Hz. The Elite Sheepskin pads sacrifice some audible bass quantity for deeper infrasonics.
More details in
https://www.head-fi.org/threads/hif...ganic-impressions-thread.890421/post-17866658 (post #11,361).
I found the Elite Hybrid pads to be dimensionally very similar to the stock pads other than their feeling flatter against the head and not seeing to implement any contour, whereby the main cause of the sonic differences should be the switch to memory foam if not also slight differences between the fenestrated leather used for the inner lining.