Does anyone know what the designations under the "motor shaft length" column stand for? I can't find them anywhere on the nameplate of my '02 merc 60/40 jet drive. I am upgrading to an '07 90/65. The '07 is a long shaft (20") and my '02 is a short shaft (15"). Was trying to find out if they might be interchangable but I'm thinking not according to the chart. Thanks.

http://outboardjets.com/Jet%20Drive%...cuments/mm.pdf