Difficult ground question

A vehicle moves thru difficult ground using top speed order, it only rolls 1 D6 to deduct from movement? I ask as there can be a perception that the top speed order is a “double” move so a roll is required for each move. I don’t think this is the case hence the question. Thanx in advance for any help received.

Hi John! A real pleasure to have you here!
You substrac 1D6 per every move. So, on a full speed move you substract 2D6 if both moves were made in difficult ground.

Regards,

Diego

Cheers mate, many thanx!