Altering plans

Hi, has anyone ever attempted to alter given plans to make a canoe longer. I’ve got plans for a 11’6 S&G canoe but wanted to add another two foot, the designer offers this option with the same mid ship height. Could I achieve this by perhaps by increasing the 305mm station lines (without me needing to buy more costly plans)? Will this work? Will the curves on the end of the panels still work at the given measurements from the last station line at the standard 305mm intervals, now that I have increased the distance of the intervals? Any thoughts or previous experiences appreciated!