Hello, I am looking at purchasing a 2008 310DA. I am trying to figure out the cruising speed at a reasonable RPM. I am seeing very different efficiency charts (I can only find a 2006 and 2009 chart online). Given the same engines, will the 2008 match this efficiency chart made for a 2009, or was there a redesign 2008 to 2009? https://www.boatingmag.com/boats/sea-ray-310-sundancer/. Appreciate any info and sorry for the "newbie" question!