Dynamic Management View (DMV) query (M_EXPRESSIONS) result doesn't appear to be correct. Why?

I am running DMVs against datsets in our Premium PowerBI Service. I was interested in analysing and documenting the M-Code behind the PowerQuery queries so I ran the following query in SSMS. This connected to a dataset called "Timesheet" behind a PowerBI file of the same name.

Select *FROM $System.DISCOVER_M_expressions

I get a single row result back  called "Agile CC" (see below). 

I assumed this result meant there is only one M-Query (M-Expression) - called "Agile CC" in this dataset behind my "Timesheet" PowerBI report. However, when I download the PowerBI file, it is clear there are many queries (25 based on the view below) in the report/dataset. For each of these queries I can see M-Code behind them (for example the "EDW Calendar WorkDate query" see below) , that isn't returned or visible from the results of the"DISCOVER_M_EXPRESSIONS" query. 

Can someone explain why I see more M-Code  in the  PowerBI file, than I can from the M_EXPRESSIONS query?

Thanks in Advance

Steve

example of query visible in the advanced editor of the PBI file, but not in the results of the DMV

Articles I have reviewed  trying to understand this. 

@https://blog.crossjoin.co.uk/2019/05/08/extract-m-code-dmv/

@https://medium.com/@martijnlentink/automate-your-power-bi-documentation-33951525c381