Interesting point. I looked around a little and there do seem to be varying definitions of “bandwidth” (=1/Q) for a peaking/notch filter. One way to experiment with this (without actually having the units) is the EQ window in Room EQ Wizard. While the -3 dB point makes sense for bandpass filters and maybe a graphic EQ (*), parametrics (digital ones anyway) seem to often use the dB half-scale value i.e. -5 dB for a 10 dB peak, -1 dB for a 2 dB peak, etc. By that definition Type II in the MicroBook does seem to be “constant Q.”

(*) I never understood how this definition can be correct even for a graphic, as the Q is undefined if boost is < 3 dB... Thank you for your interesting comment.

http://rane.com/par-c.html#constant_Q
http://www.klarkteknik.com/faq-06.php