I have a perfectionist as well and things got pretty ugly last year at this time. He is much better now but we still run into the issue here and there just not as often as before.
I highly recommend Freeing Our Families from Perfectionism by Thomas Greenspon. As a matter of fact I probably should reread it myself.
DS6 started counting on his fingers last fall too. It wasn't because he needed it, it was because they told him to do so in school! I told him that he could count without using his fingers and that was the end of it. Some of your DD's comments may be coming from school too. You know a teacher pointing out her mistakes or bad handwriting.
