An over-speed event will be recorded when the set over-speed limit is exceeded for more than 60 seconds, overspeed events are stored with the start and end time of the event and the maximum and average speed of the event, as far as I’m aware pressing OK to get rid of the visual warning has no effect on what’s recorded for the event, if the over-speed lasts for more than 60 seconds the over-speed event end time will be recorded when the speed is reduced to no more than the set over-speed limit.
As far as I’m aware if the speed is reduced to the over-speed limit within 60 seconds no over-speed event should be triggered regardless of whether or not you clear the visual warning on the tachograph display.
(To be precise, unless things have changed an over-speed event with a duration of 00:00 will be recorded)
So to answer your question I’d have to say that each over-speed event should be recorded separately and not clearing the visual warning should make no difference to what’s recorded.