Your assumptions are correct. Pitch-Freeze sets the pitchshifters to no pitch, to lock in whatever is recirculating in the reverb. Pitch+Verb-Freeze actually sets the verb to infinite as well as sets the pitch shifters to no shifting. I implemented this in the pedal and wrote the original description in the update, but honestly I'm not sure how to make it less ambiguous. I admit it's a bit of a tricky concept, but it's based on the structure of the algorithm. You guys seemed to get the gist of it though :). Sorry I missed the first query.
Because the Pitchshifters are in a feedback loop (thats what makes the pitch climb), there's no universal way to get a proper Freeze with pitchshifting still going. It's a conservation of energy problem. The pitchshifters are shifting energy higher and higher (or lower and lower) in the spectrum until we run out of spectrum (digital systems are bandlimited). The reverb in Shimmer is different that the others in Space, in that, the only way to do Infinite decay is feed it back into itself, and with ptichshfiters in the feedback loop…well you see where the problem lies. The Pitchshifters need to be shut off.
However, I found this did give me two musically useful options, but they were'nt the ones I was originall shooting for.