Offset modulation changes the target track's time offset. The target track can be any type except tempo. Each step value is interpreted as a signed timing offset in MIDI ticks. Positive values delay the target; negative values hasten it. The offset modulation is added to the track offset. If a target has multiple offset modulations, they're summed.
To work around the limited range of a step value, offset modulation supports scaling. If the modulator's duration is non-zero, the step value is multiplied by the duration to produce an extended offset. Large offsets suitable for resynchronizing song sections can be created in this way. Scaling also allows offset to be applied in convenient units such as beats or measures, by setting the modulator's duration to the desired unit length in ticks.
Offset modulation is similar to position modulation, except that the shift is specified in ticks instead of steps. This makes offset modulation ideal for time-shifting a group of tracks that have different quants. Another difference is that offset modulation can affect swing, whereas position modulation never does. Offset modulation can cause events to be skipped, and if this is a problem, use delay modulation instead.
Offset modulation can cause multiple overlapping instances of the same note on the same channel. On some instruments this may produce undesired artifacts, such as notes being cut off prematurely. For this reason, you may want to prevent note overlaps.