Selecting cells to sum based on LAST occurring incidence of criteria

Hi Excel forum,
I hope your amazing members can help me with a function issue I have.

I need to create a formula that counts based on multiple criteria - a simple COUNTIFS you might think. But alas this is not satisfying the needs.
The function must select the LAST occurring incidence of criteria and sum that.
E.g. data is categorised as:
Person number ( person 1, person 2 etc), date, status (Start, Include, End, and can have several occurrences of Start and end over time with several Includes within each group), value to be summed.

What I need a formula for is to search for the LAST occurring START and count everything from there to the current cell's timepoint, or to the last "END" status prior to this cell's date.
It is likely that there will be varying numbers of records between each "START" and "END" status. I need a formula that can dynamically identify only the last "START" and commence counting from there to the current position for the selected person in that row.

Not sure I've explained this accurately enough, so I have mocked up a simple spreadsheet - see attached.
I hope this demonstrates my requirements.

Is there a formula that could generate the required results?

Thanks in advance