*sigh* It's like deja vu 24/7 on this site
If you take a look at the score for both pieces you'll realize that they each have their own differences. What 'levels' usually mean is that someone who's a 'level 7' pianist has the necessary knowledge and skills to play the work of interest to a decent level. It does not mean that:
"if you can play one piece from level X you can play all of them" or "all pieces of this grade are equally challenging"
Not even close. Especially for people who aren't trained properly, ie people who think they're getting better just because they played one or two 'hard pieces'. It doesnt work like that. If you took the time to actually look at the score, you'll notice that no. 3 further elaborates on the difficulties of no.2 like excessive ornamentation and the scale runs.
So my advice is, instead of looking at the 'grade' of the piece, look at the score and see if you can handle it. If you're unable to evaluate your own strengths and weaknesses then chances are, you're not ready for it.

'Grades' are not the law, especially pianostreet grades.