Large units and which terrain table to roll on

Hi All

When counting up if you have more mounted or foot troops how do you count large units.

Is it a single unit or is it a large unit made up of two regular units?

I cant decide which makes more sense.

It is called a large unit so part of me thinks one unit, but you have paid for two or more units to make it and bits of the rules then talk about the front or rear unit so I change my mind and think you count up the number of individual units making up one large unit.

I think in my mind it is the second option that is winning out.

Cheers

a Large Units of 2 counts as 2 for that table.
They act as a sigle Unit but they are 2 Units.

Thanks