Large amount of data, sorted and subtotaled. Trying to filter but SubT Values turn to 0

Okay I have used the filter and sort functions countless times. Here is my issue (I will paste pic below).

This worksheet is sorted by column H, and then I used the subtotals function to put subtotals at every change in the value in column H.
What you see here is several rows of data summarized into just their subtotals using the "Hide Detail" command from the Data portion of the Ribbon. For the sake of brevety, I have pasted a printscreen from my worksheet, that shows what the full data looks like before any filtering.

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As you can see above, before filtering, all values can be seen. What I was trying to do after subtotaling, was to show just the employees that had Overtime (Column M). But the minute I put a filter on, and select only those values that are GREATER than zero, the values you see here turn to zero (see below). So do the subtotal values as well./ Can you please help me, because I have done everything and have been working on this for hours and I am ready to chuck it.

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