make excel macro for datafeed file

I have an excel file, that already has existing macros. i need to make a macro with following conditions:- When i run this macro:- 1) everytime it finds a new sku number under SKU column, it will make 15 copies of all the data in that row. So there will be 15 identicial rows with same data 2) in these identical rows, the following changes need to be made. Under "Size" column, the sizes will change from 3, 3.5, 4, 4.5, 5, 5.5, 6....till 10.5 (basically 15 values, one each for the 15 rows) 3) under column "isprimaryvariant" the row with size value 7, will have value "Yes". Other rows will have value "No" all other values remain the same. it is very important that this does not break any existing macros on the file and cause any errors. This is very simple and easy work. I have attached a sample file for you. I need it done very fast within next few hours