Calculate Purchase frequency

Try something like this:

Measure 2 = 
COUNTX(
    FILTER('Table',
    'Table'[Sales Check] > 1
    ),
    'Table'[Sales Check]
)

The issue is your measure works fine and it is doing what you asked. Remember measures are recalculated for every place they are used.  The total lines do not have a different formula that just sums what is above it. It recalculates the measure based on the filter context of where it is, which is the total line with no filters for the ID. So, in your total, the measure is recalculating and doing this:

1. Is sales check > 1? Well, what is sales check on the total line? It is DistinctCount(table) - on the total line, that is the entire table. So the distinct count is 158. So yes, 158 > 1, so the result is True.
2. Therefore return DistinctCount(table) which is 158, and that is what you see.

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Basically, there's a filter context on each row of your table, e.g. ID_Name = 1 is the filter context on your first row. But the issue is with the Total as there's no such filter on that. 

Here you can try use HASONEVALUE to check if Id_name has single value. If it's return false, it means you are on "Total" row, which means there's no Id_name filter on that and it returns all values. 

I might suggest you take a look below, which might help. 

https://community.powerbi.com/t5/Community-Blog/Fixing-Total-Errors-In-Power-BI-I-Know-It-Can-Be-Frustrating/ba-p/552929

GKs , Try like

countx(filter(summarize(Table1,Table1[id],"_1",[Sales Check]),[_1]>1),[id])