VBA - Index double match and insert values in range

Hi

To clear things up : im a vba newbie

I have done a bit searching online but i havent found any help online.

I have a workbook (A) where i import new data from
another workbook (B) on a daily basis.
The reason for this is because the data in B is updating itself from another system and i am not allowed to edit anything in B.

My basic idea is that i want to import the sheet named Book_1 from B into A so i can add comments and import this sheet on a daily basis so i always have the updated data from workbook B.

The data from book_1 populates range A to K, so i use range L for commenting

I have solved most of the problems, but i want to improve the workbook by moving some formulas into VBA to speed things up.

This is my question : Can this formula be inserted into VBA :

=IF(Ordre!A4="";"";IFERROR(INDEX(KommentarBackup!$C$2:$C$15000;MATCH(Ordre!A4&Ordre!B4;KommentarBackup!$A$2:$A$15000&KommentarBackup!$B$2:$B$15000;0));""))

The value must be inserted into Sheet(Ordre) range L4 and down as long as range A4 and down contains data

Currently this array formula is populated in another range (X4 to X15000) and i have a macro to do a copy / paste values into L4 and down. This forces me to set the workbook into manual calculation and slows things down alot

Any help i appreciated