UbiquitousBubba IANAMTP (I Am Not A Music Theory Pedanticist), but I think the reason the Am note does not lie on either a line or a space is because the bass is, once again, out of tune.
bapu Notice how it's not quite on a line or space?
Zonno bapu Notice how it's not quite on a line or space? Unfortunately, this cannot be done in the current staff view. I'll put in a feature request.