Improved skimish question

[kpumphre]

I'm sure it's obvious but if I take this feat and say we are in a crowded hallway and I can only move 10 do I still get my normal skirmish ability with out the boost or does having that feat make it so it's 20 or nothing. Again Like I said it's probably obvious I'm just not seeing it.

[Fouredged Sword]

When you move 20ft you get the bonus skirmish damage. When you move 10ft you do not get the bonus skirmish damage, but you keep your regular skirmish damage.

[Cog]

Improved Skirmish does not overwrite your basic ability, it just gives you additional benefits for moving further.

[kpumphre]

Ok, I just wanted to be sure thank you