The simultaneous temporal relation may obtain either in 'simple' or 'perfect' contexts. Modelling of this distinction originates from [Reichenbach 1947], who suggested using a third point in time, 'reference point', to capture all possible tense distinctions. In all 'simple' temporal relations, the reference point coincides with the location of the event spoken about. 'Perfect' tense meanings are created when the reference point is separated and moved away from the event time, thus altering the viewing of the temporal location of the event even though the event's actual location with respect to the deictic centre remains the same.
A common instance of a simultaneous temporal relationship obtaining in a 'perfect' context occurs when the reference point is moved away from the event time and located instead before the moment of speech. The event time is still simultaneous with the moment of speech, but it is viewed against a stretch of time which began at the reference point and continues up to the moment of speech --- e.g. the English I have lived here [for ten years] --- hence the interpretation that the event which began in the past extends up to the moment of speech. In some languages (e.g. English) this tense meaning is labelled as (one of the uses of the) Present Perfect, in others (e.g. Polish) this meaning may be collapsed with the 'simple' simultaneous meaning and labelled simply as Present.