A couple more thoughts...the letter starts off as "We"...
We are a group of individuals...
Later in the letter the person writing says "I will call you" ... not very consistent. Why not say "We will call you"?
The next sentence says "The delivery will be exhausting so I advise you to be rested."
After that, it switches back to "we"... "If we monitor you getting the money early, we might call you early to arrange ...."
Again, next sentence ... "Any deviation of my instructions will result in the immediate execution of your daughter."
Sounds to me that PR was rushing things and didn't have a chance to proof read her work.
Don't you think if someone came to the Ramsey house with the intent of kidnapping Jon Benet they would have had the note typed up already? Why risk being caught in the house in the time it would take to write a 3 page ransom note?
Also, the police overlooked the cellar room where JonBenet was. The Ramseys knew she was there. If they went to that room right away the police would be suspicious if one of them went down there right away, because she was supposedly kidnapped right? JR had to go down there later in the day and reveal that he found her, because if he never went down there the police would have to operate under the assumption she truly was kidnapped. If he waited any longer than he did that would have aroused suspicions as well.
Make no mistake, this was thought out.