The DSP allocation rule for Mod Delay is:Mono delay , two of any type (sShort, slap, medium) per chip.Stereo delay, one of any one type (short, slap, medium) per chip.This means that when instantiating a mono delay plug-in, the system will only allow two short delays on a chip. If you try to add a third short delay, the system will pull a new chip if available. If you tried to add a mono slap delay for example, it would instantiate it on the same chip as the short delays. The same rule applies for stereo, you can only have one "type"per chip.