Calculation of MTTR/MTBR

Dear expert

I want to know that Is it possible that MTBR is calculated based on today's live date.

Means Suppose example

1st working Hr-200 Hr

1st Breakdown Hr-10 Hr

2nd working Hr-300 Hr

2nd Breakdown Hr-20 Hr

MTBR=(200+300)/2-Currently system giving this data

Now I want that system should calculate like this

MTBR=(200+300+(Working Hr till date))/2

Is it possible?