When overlaying by Event in Scope View, why sometimes do the pages I've selected split in to several Averages?

The 'Event' Mode in Scope View can only Average Events within the same Recording Block as each-other. For example, if you have 2 Events in one Block, and 2 Events in another and try to Average all 4 Events, Scope View will create 2 separate Averages of 2 Events, instead of a single Average of all 4 Events.
In the below example, Pages (Events) 3 and 4 are in one Block, whilst Pages 5 and 6 are in the following Block. As a result, when trying to Average these 4 Pages, Scope creates 2 Averages:
(This is usually preceded by the warning message ''One or more of the pages you are combining have data in different underlying Chart View blocks. If you continue, several averages will be formed').
You can get around this issue by adding Comments at the point of each Event Marker, and then switching to overlay by 'Comment' in Scope View. 'Comment' Mode has no such restirctions on Averages only being able to be completed within the same Block.