Re-do your measurements, save it under a different name so you can use your old settings if you prefer.
Not a big deal...

sharke
I decided to forgo basic nutrition for a few weeks and upgraded to an RME Babyface. Very impressed with the sound so far. In fact I wasn't expecting it to sound that much different to my old Fast Track....lol.....it sure does though.
 
First thing on my mind - does this mean my original ARC2 measurements will be slightly off because of the difference in sound? Is it worth redoing them? Luckily I was too lazy to remove the little pieces of tape I stuck on the floor to mark out the positions...so it's not that much of a big deal if I have to 

Sharke, that shouldn't make a difference at all. If you DO try it and hear a difference, your mic positions were slightly different from the first time you did the corrections. The only times you need to re-correct:
 
1. New monitors
2. New positioning/moved old monitors
3. Added a sub
4. Updated ARC software where IK tells you that a new correction will be needed (this only happened once to me)
 
New interfaces shouldn't make a difference really but if you have the time and don't mind doing the correction again, (I hate doing them with a passion) give it a shot and see if a difference exists as well as how much of a difference there may be. I don't think you'll notice anything though other than if you:
 
a) pay more attention to detail this time around doing the correction positions....or less detail
b) more detail to mic placement/set-up or less detail
 
What I mean by that is....quite a few guys on the forum have done what I like to call "the ARC quickie correction". It doesn't yield great results. They contact me and I send them my detailed correction method and it totally changes their game.
 
They may have done the correction the first time by eye instead of using a tape measurer. They may have forgotten to turn off input monitoring in their interface. They may not have paid attention to the "at your nose and ears" placement of the mic. They may not have gotten enough signal at the "OK" screen.
 
Changing these things can make a huge difference. For some, the differences for the better are unreal. For others, the difference sometimes end up worse than the "quickie" corrections. It depends on the situation and the monitors really. At least that's been my experience. Good luck man. :)
 
-Danny

Thanks for the advice Danny. So you reckon precise tape measurements is the way to go? I did put some time into taping the positions on my floor (they're still there now, lol) but I can't remember how precise I was with it. I may well have used a tape measure for the horizontal distances from center position, and used the floorboards as a guide for the vertical positions. I think I may well give it another go at the weekend to see if my correction curve is similar to the first attempt. All I do know, however, is that at present it cleared all of the mud and boom out of my bottom end and made the top end come alive. 

Definitely, Sharke. The more precise, the more ARC makes a difference for the better in my particular experience. Everything has to be symmetrical as well as set up just right. As soon as you don't do something just as it should be, you notice it leaps and bounds when you do a new correction that has a more disciplined approach. The more I did quickies and didn't pay attention to detail, the more I noticed things sounding more flat and natural when I DID pay attention to detail with a new correction.
 
ARC removed a ton of congestion for me on my NS-10's and made them useable for me. It also removed the low end that was driving me crazy in my Adam's that sounded great yet was too dominant during mixing/listening. It did the exact same thing to my KRK's. This low end issue was forcing me to mix bass light. 
 
I'll pm you my ARC guidelines that have always worked for me. They are probably nothing that you haven't already done, but if by chance you may have missed something, I probably bring it to your attention in this. :)
 
-Danny  

Thanks Danny, they were in fact very helpful indeed. 

You're quite welcome. :)

Instead of precise tape measurements on the floor, I took an old bed sheet, precisely marked it and lay that on the floor whenever I redo my measurements.
That way, it's consistent and faster for me...

gustabo
Instead of precise tape measurements on the floor, I took an old bed sheet, precisely marked it and lay that on the floor whenever I redo my measurements.
That way, it's consistent and faster for me...

That's not a bad idea. I don't have an old bed sheet but I guess I could mark it out on some construction paper and keep it rolled up in a tube for future use.