I'm a grammar geek, so I definitely found some annoying things. Maybe try to use less words and be more specific. Here are a few...
-The "First of all, thank you for your interest..." should be ABOVE the "payment information" section. It's an introduction and has nothing to do with payment specifically.
-ToxicNothing got the next one that irked me...
-I'm assuming you will be sending this directly to your client, so maybe instead of saying "the client" every sentence you can just say "you". "Information required from YOU". Doesn't that have more impact?
-"At this point,
you have the opportunity to request further changes on the tracks to make sure
everyone is content with the
final mix." FINAL MIX is important and emphasizes their final chance to change things at the mixing stage. "End results" could be about anything not necessarily mix-related (maybe mastering?) Be specific to avoid confusion.
Honestly the entire document is a bit long winded. I'd bet that for every 10 people you give this to, maybe 5 people will actually read it, and 2 might get it right. I always prefer the "long story short". Leave out your justifications for WHY you need things done. Make it a laundry list that says, "I NEED YOU TO DO THIS: 1., 2., etc." No explanation, just direction. Maybe the person reading does not agree with your reasoning. Don't give them the opportunity to do that. Just tell them exactly what you need. Even with the best possible formatting, many people are morons and will still not get it right.