Issues with DATESBETWEEN

I haven't checked the numbers but the reason these dates are included is because the model is using Auto date/time option, i.e. date tables are created in the background and these are included in your hierarchy.

So you can switch off Auto date/time and create your own date hierarchy.

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I also have an opinion on the date table used in the model - it's not a date table in the true sense i.e. contains all dates over a period.  DAX date functions are really best used with  proper date tables.  The model and measures may work for you (which is great) but please be aware of the possible problems.