Why mention yom tov? (Shabbos 95a)

The gemara quotes a tosefta from the 10th perek of Shabbos that says (from kollel iyun hadaf):

If one milked, curdled milk or made cheese the Shi'ur of k'Grogeres, swept or Ribetz (sprinkled water to prevent dust from rising) or removed cakes of honey from a hive: If he did so on Shabbos b'Shogeg, he is Chayav Chatas; if he did so on Yom Tov b'Mezid, he gets 40 lashes. Chachamim say, these are forbidden only mid'Rabanan.

Why does this Tosefta all of a sudden mention yom tov? Is there an added chidush by yom tov? This is smack in the middle of maseches Shabbos so it could have easily said b'shogeg chatas and b'meizid misa. Why all of a sudden the need to mention yom tov?

I think that Tosafos' question (d"h v'harode) can answer my question. There is a huge chiddush by yom tov because you might have thought that these melachos shouldn't be chayav on yom tov because of ochel nefesh. The chidush here is that according to R' Eliezer you are chayav despite the normal heterim of yom tov.

I'm not going to explain here the answer of why R' Eliezer says you're chayav anyway but there's a lot written on it. I think that the Ritva does a good job (especially if you use the MHK edition) of summarizing the opinions. It's not even clear if R' Eliezer is really mechayev in all the cases or only in the last three. I was just really bothered by the fact that yom tov was mentioned at all and Tosafos answered that question for me.