Halliday & Matthiessen (1999: 112):
In general, there is no temporal constraint between the projected and the projecting figures: the projected figure may be past, present or future relative to the projecting one. The dimension affected by projection [is] order of reality, not time. However, there is a major dichotomy between two types of projection which does have temporal implications. To explore it, we have to look briefly at a fundamental interpersonal category, that of mood.