* From the Z80 perspective, the stuff with 180..210ns timings reacts immediately.
* However, the LRQ high duration of 15..41us is visible to the Z80 (though any existing and any well programmed Z80 software should not RELY on the presence of this delay) (it should of course be able DEAL with it, ie. it should not send new allophones while LRQ is high) (caution: The SSA-1 detection in "Roland in Space" DOES rely on the presence of that delay).
* Theoretically, in standby state, the chip could process incoming data immediately, so LRQ wouldn't need to go HIGH at all. The fact that it does go HIGH may have two reasons: First, the chip may be unable to react immediately. Second, it may be done intentionally, for use with edge-triggered IRQ or DMA hardware.