Su-27's Flaperons position doubt

Hi there

Just curious… Have you guys noted that the Su-27’s flaperons are lowered about 15 degrees during landing, no matter the aircraft’s weight?(except the naval variant) Why is that? I mean, when a Flanker is a static display during an air show, the fighter’s flaperons are lowered much more( I think 30 or 45 degrees) than when it’s landing. Why the plane doesn’t use its flaperons as lower as when during static display? Is there some aerodinamics restriction or something?

Thanks