Angie, you've figured out it is the blade setting but the sole plates are easy to check. With the toe plate tightened down to be level with the heel plate, a straight edge should sit flat across the entire length of the bottom. The only problem you can have is that the toe plate isn't parallel to the heel plate. The blades should be set to be dead level with the heel plate and that should eliminate the snipe, however, I have also had problems trying to get mine to work decently at this setting. I should note that the machine worked perfectly when it was new with new and sharp blades and only caused problems after multiple sharpenings.
I found a new set of blades for my machine on ebay for $7 at which time I also found out that my machine is one of over 20 that uses the same blades and is made by the same manufacturer in China or Taiwan. The Hitachi model even uses the same 1900B model number and is identical except for the colour.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.