The reasons for the phrasing of 20-21 can be demonstrated by page 19.
1) If you take into account the flow of the bubbles, "love" fits just fine. Negi devoted 3 panels at the bottom of 19 to show Miku pointing at Fuut. She's simply pointing at the object of her emotion and stating her emotion. She's just autistic / dorky that way.
2) The way Miku phrased it in page 20-21 is NOT consistent with how she said things in page 19.>are mo suki>are mo suki>kore mo suki
My interpretation is that this is very intentional to show Miku being too embarrassed to say it clearly / directly. But she's still conveying it in a very definite way.
I try to take the speaker's personality and the author's intentions into account when I translate. That's why sometimes things sounds a bit awkward. My assumption is that people want to read Haruba Negi's 5toubun no hanayome, and not worldthre- the scanslation team's version of the Quintessential Quintuplets. If you don't like it, feel free to replace page 20-21 with the other group's when you archive it.
I apologize if I missed giving out any (you)s.