If you can rephrase your problem I am sure you may get some answers.

1. When you import your data what is the display of your sheet ?
ie. how many columns and what are the column labels ( jan feb
etc.)

2. "problem is the length of the columns will be dynamic so I need to
calculate a
range of cells for which percentages and totals are required
" ????

Do you insert new columns for totals and %'s ?

3. "jan count column will lengthen if feb has more TYPEs" ????,"so I
have to
re-populate cells for totals/percentages" ??????

I dont' think your problem is increasing the widht of a column.