Criteria based count values - Formual Modification!

Hi,

May I request for a small help!

I have this formula:

 =COUNT(INDEX(B3:M3,MATCH(TRUE,INDEX(ISNUMBER(1/B3:M3),0),0)):INDEX(B3:M3,MATCH(3,INDEX(1/ISNUMBER(1/B3:M3),0),1)))

But this may be required to be modified to help me arrive at the count.

The products are be paired in 2, 4, 6 or 8 and so on…. The basis of the counting is the to be the 1st row for ever paired product. Net net if there are 4 products than 1st or 3rd row would form the basis of calculation which ever has the first value greater than 0.

Attached is a sample of my purchase report. The cells to be calculated are highlighted in RED for ease of understanding of my request.

Hoping for your help! Do let me know if any further clarification is required.

Many thanks!