Would be easy if it did, but I edited my description to 316 characters last night.
EDIT: To clarify, I didn't muck around with the maxlength in add, so if there are restrictions on that behind the scenes then two thumbs up. But on edit, my original description was 290-something characters (I think), exceeding maxlength, so that's affected by the suggestion to increase it here. But I forced in the new tags and description updates, and it successfully saved with 316 characters (154 summary sentences and the rest tags, so I follow the spirit of the add function if not the edit box). So 255 doesn't appear to be a hard limit for edits. Still, I haven't tested the boundaries of that and don't intend to; hopefully it does truncate before it would become a visual issue in the archive if someone did more. Regardless, I think 255 should be higher because tags.
I'm dodging specifics on exactly what I did because I don't want to encourage everyone and their grandmother to try it out, but if you want a step by step, I can try Skype or something.