I have a 102 cubic inch pushrod V-twin. I have always used Rotella T 15w40 5qts of it, with good results. I have a 4qt jug of the Rotella Synthetic 5w40 and one quart of the non syn Rotella T 15w40. I want to use up this left over bottle of 15w40 and just mix it in with the 5w40, does anyone see any problems or issues with this? I change my oil once a year and ride 1700-3000 a year so I dont see this being an issue, what do you guys think?