VB6 convert MSHFlexgrid1 cells no2

Hi,

This topic follow the previous one on this link:
https://www.experts-exchange.com/questions/28959455/VB6-convert-MSHFlexgrid1-cells.html?anchor=a41728752&anchorAnswerId=41728752#a41728752

I need to add 1 small thing to previous code when in column 4, i need to add a sequence number.

Just as a recap:
What i would like to do is that if i have multiple rows with the same value in column 0, 1 and 11, it will leave all cell populated  as it is and also add the letter "H" in column 3 of the first row only.
Then, it will empty the value in column 2 and add the letter "D" in column 2.

Now i want to add in column 4 the sequence number always matching column 0, 1 and 11 combination.

Ex:

Before:

After macro:

How can i do that?

Thanks for your help
Filter-grid.zip