I'm guessing you either bought a very small roll or your boat has more windows then the average house ?
When I did the house I bought the commercial 30M roll of 20% and a 10M roll of 35% for the windows and sliding doors fronting the neighbors window to avoid any mismatch issues problems and 1.5M wide to reduce wastage as most window heights were in the 1200-1500 range. Even if there are 2 different batches and may not be an exact match they should still be close enough not to notice the difference with naked eye.
When you compared them did you compare 2 pieces of window tint with backing still on them or did you compare the new roll with backing still on against the tint on your window in which case could the backing account for the blue tinge ?