I think what Orion is saying (and I agree) is "Don't sweat the small stuff." Hunting for agents and/or publishers is frustrating enough without spiraling down into the minutiae of it all. Sometimes it's a good idea to take a step back, look at the questions that are buzzing round inside your head, and say "Wait a sec. Is that really important?"
Agents and editors are human beings, not computers narrowly programmed to trash your submission if you're a micron off the straight and narrow. You need to have the basics down, and make every effort to follow guidelines--but within those parameters, there's quite a bit of wiggle room. Always assuming, of course, that you have a marketable manuscript. If you don't, all the rule-following in the world is not going to make a difference.
- Victoria