DO FLAT-FITTED RGPS INCREASE SCARRING IN KERATOCONUS?

Optometry & Vision Science. 82(12):1014-1021, December 2005.
According to this study:

"A greater proportion of the corneas wearing flat-fitting contact lenses were scarred (43% compared with 26% for the steep-fitted eyes)"

But then it says:

"After controlling for corneal curvature, the association of rigid contact lens fit and corneal scarring at baseline did not persist. 32% percent of unscarred eyes at baseline fitted flat had developed an incident corneal scar by the eighth year follow-up visit compared with 14% of eyes fitted steep."

And the study concludes:

"The data reported here indicate that, after controlling for disease severity in the form of corneal curvature, keratoconic eyes fitted with a rigid contact lens resulting in an apical touch fluorescein pattern did not have an increased risk of being scarred centrally at baseline."

Huh? Conclusion does not seem to match the results. What does it mean when it says:

"after controlling for corneal curvature"?

I guess I'll continue as I have been with keratoconics: 3 point touch and watch for scarring. Piggyback if scarring begins or flatten a little.