By default, Data Discovery will produce each measure with an abundance of aggregation types – sum, avg, cnt etc. This is just to ensure that all options are available to the end-user, as Data Discovery is not able to make a qualified decision on e.g. one proper aggregation type. You may however lessen the options by making this qualification yourself.
First, edit the cube and then work with Attribute settings options on the fact table.
In the example below, only the two Amount fields will become measures, and only as Sum measures. All the other fields have been marked as Dimensions only fields.
In the TARGIT client’s Source Data tab, this will likewise produce a less confusing picture: