Macro To Count Data With Exeptions

Hi

Could someone please have a look at this, I have attached a sample and will try and explain what I would like. I am not sure if a macro will do this or maybe some other way

In B3 I have a number that calculates how many full pallets I have, this is done by looking down columns J, M, P, S, V, Y, AB & AE , Each column is a different week 1 – 8.

D Column = Layer
E Column = Full Pallet

In the sample file you will see that in J5 I have ordered 11 which is 1 layer as seen in D5, we know that in E5 the full pallet is 77 so this is 1/7th of a pallet

In J8 I have ordered 16, again if we look at D8 you will see this is 1 layer and in E8 the full pallet is 160, so this is 1/10th of a pallet

This continues all the way down the sheet and B3 should read something like 2.72 pallets

The problem I have is when data is put into the next column which is M column (week2) I would like it to stop looking at the J column (week1) and just give me the results of M, and so on right through to AE column (week8)

Is this possible? Thanks very much in advance for any help.