SIR is a bit of a special case
it introduces a fixed delay - this is why I dont use it, even tho its clearly a billion times better than any other native verb i have - i guess what Ott is complaining about also.
yes, you can shift the audio backwards, or whatever, but thats a pain in the arse when you want to use it as a send or as part of any remotely complex routing.
my *guess* is that he's making a version which doesnt have this fixed delay - sure, it might have its own latency of processing time, the same as any other plugin (eg, when i run a signal through a channel with a waves RCL, and simulaneous through another channel without, i get chorus) - but this can be automatically compensated for by the host (providing you dont do what i do, and fail to upgrade to such a host, through sheer laziness)