Wrong sub totals

Hi dears

I have calculated the cost per kg, wherein the total shows wrong figure.

In the above table, powercost per kg calculated as DIVIDE([power cost], [prod qty]).

Where there are no powr cost, the column power cost per kg shows blank and that is perfect.

But when it gives sub-total for all jobs of the customer - CHERISH KNITS - the sub total is wrong

that is showing 1.81.

When I filtered the above table, removing the rows where power cost is blank, I get the following

result.

The above filtered table, shows 2.19 which is correct.

I want to achieve the above result through a measure so that

I can give the power cost per kg in a card visual without giving the above filtered table.

Your help is much appreciated.  Thanks.